FIZ4107 Assignment 1 - All posters 1

topic 4 Nur Syafiqah Syahmimie Binti Augustine
S50569
Molecules & Energy Bond

Why ionic compounds Why does water volume
like salt (NaCl) crack? expand when it freezes?
When water is a liquid, the water
Ionic crystals are hard because of tight molecules are packed relatively close
packing lattices, say, the positive and together but can slide past each other
negative ions are strongly attached and move around freely .
among themselves. Pure water has a density of 1.000 g/cm3
The electrostatic repulsion can be at 4˚ C.
enough to split or disorient completely As the temperature increases or
the lattice infrastructure. decreases from 4˚ C, the density of water
Applying pressure shifts the alignment of decreases.
the ions and results in brittleness. When water freezes, bonds are formed
It takes a lot of energy to break them that lock the molecules in place in a
apart from each other. Ions form rigid regular (hexagonal) pattern.
crystalline structures. This arrangement makes the ice less
dense than water in liquid form, thus ice
float on top of water.

Why metals such as alloys gold, or References
iron dent and bend rather than crack
like rocks coal, or glass when applied thttps://chemdemos.uoregon.edu/demos/Properties-of-
force on them? An-Ionic-Salt-0#

The valence electrons surrounding https://www.ck12.org/chemistry/metallic-
metal ions are constantly moving. bond/lesson/Metallic-Bonding-MS-
This makes metals good conductors of PS/#:~:text=The%20lattice%2Dlike%20structure%20of,b
electricity. e%20shaped%20into%20thin%20sheets).&text=Therefo
The lattice-like structure of metal ions is re%2C%20the%20metal%20can%20bend,when%20the
strong but quite flexible. %20hammer%20hits%20it.
This allows metals to bend without
breaking. Metals are both ductile (can https://www.researchgate.net/publication/322939904_U
be shaped into wires) and malleable nderstanding_and_utilizing_the_biomoleculenanosystem
(can be shaped into thin sheets). s_interface_Nanoproteomics_approaches_in_biomarker_
discovery_The_critical_role_of_protein_corona_on_nanop
articles_as_drug_carriers

https://www.e-education.psu.edu/earth111/node/842

ASSIGNMENT 1 MOLECULES &
TOPIC 4 ENERGY BOND

NAME: CHE FATIMAH NADIA Why metals such as alloys,
BINTI CHE JUSOH gold, or iron dent and bend
rather than crack like rocks,
MATRICS NO.: S51064 coal, or glass when applied

LECTURER'S NAME: DR. force on them?
KHADIJAH HILMUN BINTI
KAMARUDIN Malleability is a physical properties
of matter, usually metals.
Why ionic compounds It usually applies to the family group
like salt (NaCl) crack? 1 to 12 on the Periodic Table
elements.
The salt (NaCl) has a uniform It is ability of a metals to bend into
pattern of ions (before the force other shapes without cracking.
applied). Alloy, gold or iron are highly
If the applied force is strong malleable; usually bend and twist in
enough, it pushes the ions out of various shapes.
alignment.
The salt breaks apart because the References
applied force repositions the like-
charged ions next to each other; Chen, E. Y., Liu, W. F., Megido, L., Diez. P., Fuentes, M.,
the resulting repulsive force Fager, C., … Mathur, S. (2018). Chapter 3 - Understanding
crack/breaks apart the salt. and utilizing the biomolecule/nanosystems interface.
Nanotechnologies in Preventive and Regenerative
Why does water volume Medicine, 207-297. doi: https://doi.org/10.1016/B978-0-
expand when it freezes? 323-48063-5.00003-4
Metwalli, K. (2017). Ionic bonds and Ionic compounds.
Hydrogen bonds between water molecules Retrieved from the SlideShare website:
become stronger and cause the matter to https://www.slideshare.net/KamalMetwalli/ionic-bonds-
expand (below 4°C). and-ionic-
When frozen, water molecules take a more compounds#:~:text=The%20crystal%20breaks%20apart
defined shape and arrange themselves in %20because,force%20breaks%20apart%20the%20crystal
six-sided crystalline structures. Mythical Creator of Chinese Metallurgy & Weaponry.
The crystalline arrangement makes the ice (2001). Ancient Metallurgy. Retrieved from
less dense than the liquid water. https://pages.ucsd.edu/~dkjordan/arch/metallurgy.html
When water freezes, the volume expands Structural Biochemistry/Unique Properties/Expansion
by approximately 9% and ice floats a top upon Freezing. (2020). Retrieved December 26, 2020,
water. from
https://en.wikibooks.org/wiki/Structural_Biochemistry/U
nique_Properties/Expansion_upon_Freezing#:~:text=Wh
en%20frozen%2C%20water%20molecules%20take,dense
%20than%20the%20liquid%20water.&text=Thus%20wate
r%20expands%20as%20it%20freezes%2C%20and%20ice
%20floats%20atop%20water

FIZ4107 ATOMIC PHYSICS (S202021-I)

ATOMIC
Nik Aisyah Najwa Bin

Q1 : WHY IONIC COMPOUNDS LIKE SALT Q2 : WHY DOES WATER VO
(NACL) CRACK? FREEZ

Ionic compounds has ionic holding that includes When we cooling the wat
the exchange of electrons and this circumstance less for a few reason whi
ordinarily happened when a metal bonds with The reason is since of t
non-metal. So, for the NaCl compound which is particles. The oxygen iota
salt, Natrium (Na) exchange its electron to the the hydrogens are margina
Chloride (Cl) which is non-metal and shaping an water particles tend to sta
ionic compounds. called hydrogen bonds.The
connect together within t
It takes a huge sum of mechanical drive, such as for it adopting that shape
striking a precious stone with a pound, to open structure with enorm
constrain one layer of particles to move relative to part of additional spaces.
its neighbor. Be that as it may, when that happens,
it brings particles of the same charge following to When water solidifies, the
each other. The awful powers between like- the foremost steady arra
charged particles cause the gem to smash. When have the minimum amoun
an ionic precious stone breaks, it tends to do so about ice crystal. It so h
along smooth planes since of the standard course action of water particl
of action of the particles. prerequisite is one that ta
And so ice extends when it

REFERENCES

1. Intermediate, C. K. Chemistry for Non-Majors. https://courses.lumenlearning.com/che

2. Smith, C. (2009). Why does water expand when it freezes? Questions | Naked Scientist

when-it-freezes.

3.Brainard, J. (2020, May 18). Metallic Bond. CK. https://www.ck12.org/chemistry/metalli

PHYSIC

nti Abdullah (S51106)

OLUME EXPAND WHEN IT Q3 : WHY METALS SUCH AS ALLOY, GOLD, OR
ZES? IRON DENT AND BEND RATHER THAN CRACK
LIKE ROCKS, COAL, OR GLASS WHEN APPLIED
ter, the particles are vibrating
ich make the volume grows. FORCE ON THEM?
the bizarre shape of water
a is somewhat negative, and Metallic bonds are powers of fascination between
ally emphatically charged, so positive metal particles and the valence electrons
ay together shaping what are that are always moving around them. The valence
e way water particles tend to electrons incorporate their possess and those of
the fluid state which needed other, adjacent particles of the same metal. The
e where it'll form an awfully valence electrons of metals move openly in this
mous gaps. Meaning , there's a way since metals have moderately
electronegativity, or fascination to electrons.
particles get themselves into
angements or positions that The lattice-like structure of metal particles is solid
nt of vitality within the coming but very adaptable. This permits metals to twist
happens that the course of without breaking. Metals are both bendable and
les that best fulfills this moldable. The press particles can move inside the
akes up indeed more space. “sea” of electrons around them. They can move a
t solidifies. small closer together or more distant separated
without breaking the metallic bonds between
them. Hence, the metal can twist instead of split
when the pound hits it.

eminter/chapter/coordination-numbers/.
ts. https://www.thenakedscientists.com/articles/questions/why-does-water-expand-

ic-bond/lesson/Metallic-Bonding-MS-PS/.

#ATOMICPHYSICS

Molecules &
Energy Bon

NAME : Noor Shazwani binti Abas
MATRIC NO : S51112
LECTURER'S NAME : Dr. Khadijah Hi

Why does water volume expenses when it
freezes ?

When freeze, water molecules take a more
defined shape and arrange themselves in
six-sided crystalline structures.
The crystalline arrangement is less dense
than that of the liquid water.
Thus, water expands as it freezes
and ice floats a top water.

Why ionic compound like salt (NaCl)
crack ?

Before the force is applied, the salt
has a uniform pattern of ions.
If the applied force is strong enough,
it pushes the ions out of alignment.
A repulsive force created by nearby
like-charged ions breaks apart the
crystal

Tfbhloiekertcecsaor-aeaeucpeshlrsatfaueaoerc(prltrNthtog/ciahnecesoCrgedsitatl)rahiicbooecpkerrpnnrpeasstulaih;clentskktedheshivxseeetalt.

&
nd

ilmun Kamarudin

Why metals such as alloy, gold or iron
dent and bent rather than crack like

rocks, coal or glass when applied force
on them ?

Malleability is a physical properties
of matter,usually metals.
It usually applies to the family group
1 to 12 on the periodic table
elements.
It is ability of a metals to bend into
other shapes without cracking.
Alloy, gold or iron are highly
malleable, malleable metals usually
bend and twist in various shapes.

REFERENCES :
"Zinc, Chemical Element-reaction uses, elements,
examples, metal, gas, number, name".
www.chemistryexplained.com. Retrieved 2019-10-05.
Roy, J., (2011). Bulk drugs or active pharmaceutical
ingredients. An Introduction to Pharmaceutical
Sciences, (2011).

Mohd Faris Izwan B Abdul Aziz

1)why ionic compounds 3)Why metals s
like salt nacl crack or iron dent an
crack like roc
 Ionic crystals are hard because of tight
when app
packing lattices, say, the positive and
negative ions are strongly attached among  Metallic bonds are
themselves. attraction between po
and the valence elect
 So, if mechanical pressure is applied to constantly moving aro
ions form a lattice-lik
an ionic crystal then ions of similar together by the metal
charges may be forced to get closer to  Metallic bonds exp
each other. can conduct electricit
without breaking.
 Now, by doing so, the electrostatic
repulsion can be enough to split or
disorient completely the lattice
infrastructure. Thus imparting the brittle
character.

(S51365)

such an alloy, gold 2)why does water volume
nd bend rather than expand when it freezes
cks, coal or glass
When frozen, water molecules take a
plied force? more defined shape and arrange
themselves in six-sided crystalline
e the force of structures. The crystalline
ositive metal ions arrangement is less dense than that of
trons that are the molecules in liquid form which makes
ound them. The the ice less dense than the liquid water.
ke structure held Thus water expands as it freezes, and ice
llic bonds. floats atop water.
plain why metals
ty and bend

WHY DOES WATER VOLUME WHY IONIC C
EXPAND WHEN IT FREEZES ? SALT NA

When frozen, water molecules Ionic crystals
take a more defined shape and tight packing lat
arrange themselves in six-sided
crystalline structures. The positive and n
crystalline arrangement is less attached am
dense than the molecules in liquid So, if mec
form which makes the ice less
dense than the liquid water. applied to an ion
Thus water expands as it freezes, similar charges
and ice floats atop water.
closer t
References;
1. https://chemistry.stackexchange.com/questions/33322/why-are-so-many-ionic-compounds- Now, by doing
brittle/33325#33325 repulsion can b
2.https://en.m.wikibooks.org/wiki/Structural_Biochemistry/Unique_Properties/Expansion_upon_Freezin
g#:~:text=When%20frozen%2C%20water%20molecules%20take,dense%20than%20the%20liquid% disorient com
20water.&text=Thus%20water%20expands%20as%20it%20freezes%2C%20and%20ice%20floats%2 infrastructure
0atop%20water.
3. https://www.ck12.org/chemistry/metallic-bond/lesson/Metallic-Bonding-MS- brittle
PS/#:~:text=The%20lattice-
like%20structure%20of,be%20shaped%20into%20thin%20sheets).&text=Therefore%2C%20the%20
metal%20can%20bend,when%20the%20hammer%20hits%20it.

COMPOUNDS LIKE
ACL CRACK ?

s are hard because of WHY METALS SUCH AN ALLOY, GOLD
ttices and both of ions, OR IRON DENT AND BEND RATHER
negative are strongly THAN CRACK LIKE ROCKS, COAL OR
mong themselves.
chanical pressure is GLASS WHEN APPLIED FORCE ?
nic crystal then ions of
s may be forced to get Metallic bonds are the force of
to each other. attraction between positive metal
ions and the valence electrons that
g so, the electrostatic are constantly moving around them.
be enough to split or The ions form a lattice-like structure
mpletely the lattice held together by the metallic bonds.
e. Thus imparting the
e character. Metallic bonds explain why
metals can conduct electricity and
bend without breaking.

Molecules andNurafifa Ruqayyah Binti Rushdan S51368
Energy Bond

Why does ionic compound Why does water
like salt (NaCl) crack? volume expand when
it freezes?
Ionic bond formed when a metal transfer
electrons to a nonmetal to form ions that will When water froze, the water molecules
attract each other to form a solid compound take a more defined shape and arranged
themselves in six-sided crystalline
NaCl bond by ionic bond which structure , turning into solid structure
involves tranferation of electron when
Na (metal) bond to Cl (nonmetal) The crystalline arrangement
are less denser than liquid
The salt crack when the applied force water, thus the water volume
reposition the like - charged next to expand when it freezes
each other

Why materials such as alloy, gold, or iron dent and bend
rather than crack like rocks, coal or glass when applied force
on them?

Metallic bonds are forces of attraction between metal to another
metal that involves electron pooling
The electron that surround the metal ions constantly moving
The lattice-like structure of metal ions is strong and flexible that allow
metals to bend without cracking

References

CK-12: Metallic Bond. Retrieved from https://www.ck12.org/chemistry/metallic-bond/lesson/Metallic-
Bonding
Science Direct: Ionic Bonding (2018). Retrieved from https://www.sciencedirect.com/topics/pharmacology-
toxicology-and-pharmaceutical-science/ionic-bonding
Is water ionic or covalent? Retrieved from https://byjus.com/jee-questions/is-water-ionic-or-covalent





MOLECULES ENERGY BOND

The water molecule consisting of 2 atoms

In the ionic crystal, when the force of hydrogen and one of oxygen. This
is applied, the charge particles makes the water molecules drawn
move along the crystal, causing
towards each other forming hydrogen
bonds.

their rearrangements to meet Upon freezing, the molecules set

similar charges. The repulsion themselves in a arrangement that is very
between them affects the cohesion open in nature and contains more space
than the water in the liquid state. Hence,
of the crystal, and making it crack. water is said to expand on freezing and

becomes less dense. On the other hand, it

contracts on thawing, much unlike most

other liquids.

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IRDINA SYAFINAZ BINTI MOHD NORSHAM
(S51803)

SITI NURAISAH BT SARIFUDIN (S52027)
FIZ4107 (ATOMIC PHYSICS)

LECTURER'S NAME: DR. KHADIJAH HILMUN KAMARUDIN

QUESTION 1: Why ionic compounds like salt (NaCl) crack?

WHAT ARE IONIC COMPOUNDS? IONIC COMPOUNDS FORM CRYSTALS

Compounds in which electrons are transferred A crystal consists of many alternating
from one atom to another. In this type of positive and negative ions bonded
compound, electrons actually move between the together in a matrix. Eg. The sodium and
atoms, rather than being shared between them. chloride ions are attracted to each other
When atoms give up or accept electrons in this because they are oppositely charged, so
way, they become charged particles called ions. they form ionic bonds.
The ions are held together by ionic bonds, which
form an ionic compound.

PHYSICAL PROPERTIES OF IONIC COMPOUNDS (A) The sodium chloride crystal is shown in two dimensions. (B)
When struck by a hammer, the negatively-charged chloride ions are
Shattering forced near each other and the repulsive force causes the crystal to
Ionic compounds are generally hard, but brittle. It takes a large shatter.
amount of mechanical force, such as striking a salt (NaCl) with
a hammer, to force one layer of ions to shift relative to its
neighbor. However, when that happens, it brings ions of the
same charge next to each other. The repulsive forces between
like-charged ions cause the salt (NaCl) to shatter. When an
ionic crystal, salt breaks, it tends to do so along smooth planes
because of the regular arrangement of the ions.

QUESTION 2: Why does water volume expand when it freezes?

THE MOLECULAR STANDPOINT WATER VOLUME EXPAND WHEN IT FREEZES

The water molecule, composed of 2 hydrogen atoms and one In fact, water also shows the normal behavior of
oxygen atom, forms a Mickey Mouse head-like shape, such that contracting due to cooling up to 4° C. But on cooling to
the ears are hydrogen atoms and the head is represented by the temperatures below that, it starts expanding in volume.
oxygen atom. The oxygen atom side of the molecule is slightly This is because the molecules start to get into a stable
negative, while the hydrogen atom side has a small positive hexagonal lattice structure, as mentioned above. It is a
charge. This allows the water molecules to be attracted into each very open structure with a lot of intermolecular space.
other, creating hydrogen bonds. Upon freezing, the molecules set Hence the expansion. The same applies when finally it
up a structure that is very open in nature and requires more freezes to ice at 0° C.
space than the water in the liquid state. As a result, water is said
to expand on freezing and become less dense. On the other side,
it contracts for thawing, far different from most other liquids.

QUESTION 3: Why metals such as alloy, gold or iron dent and bend rather than crack like rocks, coal or
glass when applied force on them?

WHAT ARE METALLIC BONDS? PROPERTIES OF METALS

Metallic bonds are forces of attraction between positive The valence electrons surrounding metal ions are
metal ions and the valence electrons that are constantly constantly moving. This makes metals good
moving around them. The valence electrons include their conductors of electricity. The lattice-like structure
own and those of other, nearby ions of the same metal. of metal ions is strong but quite flexible. This
The valence electrons of metals move freely in this way allows metals to bend without breaking. Metals are
because metals have relatively low electronegativity, or both ductile (can be shaped into wires) and
attraction to electrons. The positive metal ions form a malleable (can be shaped into thin sheets).
lattice-like structure held together by all the metallic
bonds.

REFERENCES

Cheng, M.M.W., Oon, P.-T., 2016. Understanding metallic bonding: Structure, process and
interaction by Rasch analysis. International Journal of Science Education 38, 1923–1944.

Stauffer, E., Dolan, J.A., Newman, R., 2008. CHAPTER 3 - Review of Basic Organic
Chemistry. In: Stauffer, E., Dolan, J.A., Newman, R. (Eds.), Fire Debris Analysis. Academic
Press, Burlington, pp. 49–83.

https://courses.lumenlearning.com/cheminter/chapter/coordination-numbers/ Eg. The iron ions can move within the “sea” of
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Modules_and_Websites electrons around them. They can shift a little closer
_(Inorganic_Chemistry)/Crystal_Lattices/Lattice_Basics/Ionic_Structures together or farther apart without breaking the metallic
http://www.iapws.org/faq1/freeze.html bonds between them. Therefore, the metal can bend
rather than crack when the hammer hits it.

Q1 - Why ionic comcpraocukn?ds like salt (NaCl) Molecules
IboonAnipcdIptcflbroyteomaitnmktpwgheioeoesapuanetarnscnedmhlasotsansohtuakdteorreh·rfeepeueeorcssp·hns.rusieIaittl·tfotrhicrtvsngkuesesiycntdmftahutouboneoerrlrdemaebittcnslortiu.regeltliegangehnaksmieed.tetsisvcshnt.reretyomiosnoftngaatsplhlaienret Energy
Bond

BY:SITI NUR IZZATI BINTI
MAZLAN (S52046)

• Q2 – Why does water volume expand when it freezes? REFERENCES
1.Anonymous. (2015, November 13). Why Are Salt Crystals Brittle?
Liquids expand since the molecules move with Retrieved December 24, 2020, from Ceramics:https://expandusceramics.
greater energy overcoming the intermolecular com/qa/why-are-saltcrystalsbrittle.html#:~:text=Sodium%20chloride%
attraction. 20has%20a% 20high,is%20in%20general%20much%20higher.
On the contrary, liquids usually contract on cooling.
It is because the molecules move slower and are not 2.Anonymous. (2020, October 29). Why Does Water Expand When It
able to overcome the force of attraction between Freezes. Retrieved November 23, 2020, from Science Facts:https://
them. www.sciencefacts.net/why-does-water-expand-when-it-freezes.html
When they freeze, they contract some more to form a
rigid solid structure with minimal intermolecular 3.Auyeung, C. (2014, January 21). Metallic Bond. Retrieved December 22,
spaces between them. But that is not the case with 2020, from CK12:https://www.ck12.org/chemistry/metallic-
water.Instead of contracting, it expands. bond/lesson/Metallic-Bonding-MSPS/#:~:text=The%20lattice%2Dlike%
20structure%20of,metals%20to%20bend%20without%20breaking.&text=
•dcQoea3nlt-,TaohWnredhgiyrblaoemsnnsediwtoarnhlassetcnshaueancrphmptaholisvaeanedllwcforoyiart,cchgekinoollitdnkh,eteohrr“eosimcerkoa?sn”, A%3A%20The%20iron%20ions%20can,the%20metallic%20bonds%20betw
of electrons around them. een%20them.
Tohrefyarctahnesrhaifptaartliwttiltehcoluotsebrrteoagkeintghetrhe
metallic bonds between them.
Tthhearnecfroarcek, twhehemnetthael chaanmbmeenrdhriattshiter

MOLECULES & ENERGY BOND

Why ionic compound crack?

The nature of the ionic compound is hard because of strong
electrostatic forces between atoms, and the positive and negative ions
are strongly attracted to each other and difficult to separate (ex. salt-
NaCl).

However, when pressure is applied to an ionic compound then ions of like charge may be forced closer to each other.

Ionic compounds are crack due to the strong bond between the positive and negative ions that make up the
molecules. These positive and negative bonds create crystals in rigid, lattice structures.

When this happens the ions in the compound undergo electrostatic repulsion, splitting the compound.

By doing so, the electrostatic repulsion can be enough to split or disorient completely the lattice infrastructure.

Ions of the same charge are brought side-by-side and so the crystal repels itself to
pieces.

How did this
happen?

Why does water volume expand when it Why metals dent and bend
freezes? rather than crack?

Water has a lower density in solid form than its liquid Metallic bonds form only in elements that are
form, due to the extra volume in its ice form. metals. Metallic bonds are forces of attraction
between positive metal ions and the valence
This is due to a phenomenon called hydrogen electrons that are constantly moving around
bonding and occurs when polar ends with opposite them.
charges of water molecules get attracted to other
water molecules. The valence electrons surrounding metal ions are constantly moving.
This makes metals good conductors of electricity. The lattice-like
Water expand approximately by about 9%-10%. structure of metal ions is strong but quite flexible. This allows metals
to bend without breaking.
On the contrary, liquids usually contract on
cooling. It is because the molecules move slower and Metals can be dent and bend
are not able to overcome the force of attraction because they consist of layers of
between them. atoms that can slide over one another
when the metal is bent, hammered or
When water freezes, the hydrogen pressed..
bonds push the H2O molecules farther
apart from each other increasing the The iron ions can move within the “sea” of electrons around them.
intermolecular space resulting in They can shift a little closer together or farther apart without breaking
expansion. the metallic bonds between them.

During freezing, water molecules lose energy and do not vibrate or This happened is helped by the presence of dislocations in the
move around as vigorously. This allows more stable hydrogen-bonds to crystal structure. Therefore, the metal can bend rather than crack
form between water molecules, as there is less energy to break the when the hammer hits it.
bonds.
When a force is applied to the metal, the dislocations move through
REFERENCES the lattice structure. Dislocation glide is easy in metals since metallic
bonding is non-specific.
Water Expansion When Freezing. (2020, October 29). Retrieved December 26, 2020, from
https://www.sciencefacts.net/why-does-water-expand-when-it-freezes.html ZAFIRAH BINTI SHAMSUDIN (S52120)

Foundation, C. (2018, September 13). 12 Foundation. Retrieved December 26, 2020, from
https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-science-flexbook-
2.0/section/5.10/primary/lesson/metallic-bonding-ms-ps

Jekyll1911. (2020, February 23). Quick Answer: Are Ionic Bonds Brittle? Retrieved December
25, 2020, from https://expandusceramics.com/qa/are-ionic-bonds-brittle.html

MOLECULES &ENERGY BOND

NURUL SHAQQINAH BINTI P.RAMLI (S52161)

IONIC METALLIC COVALENT
BONDING BONDING BONDING

Between a metal and a non-metal. Giant structures of atoms in a Formed between non metals.
Electrons in the outer shells are regular pattern. These bonds are formed when
transferred.
Electrons in the outer shell are electrons are shared.
Metals lose electrons and become delocalised. Bonds between atoms are strong.
positive ions.
They can move through the whole Can be small molecules, large
Non-metals gain electrons and structure. molecules - polymers or giant
become negative ions.
Creates strong metallic bond. structure.
All ions have the electronic
structure of a noble gas. PROPERTIES OF Examples:
METALS An example of covalent bonding is the
Example:
Lithium (which has 3 electrons and 1 in Metals are generally solids with molecule of carbon dioxide. Carbon
moderate to high melting points and has 4 of 8 electrons in its outer shell
the outer shell) and fluorine (which and oxygen has 6 of 8 electrons. By
has 9 electrons and 7 in the outer much higher boiling points. combining 2 oxygen atoms with 1
shell) trading an electron to form LiF Metals can be shaped without breaking. carbon atom, the atoms can share
electrons such that each atom has a
or lithium fluoride. Metals are good conductors of
electricity in both the full outer shell.
PROPERTIES OF solid and liquid states.
IONIC COMPOUNDS PROPERTIES OF
Metals are good conductors of heat. COVALENT BOND
Tends to be hard, rigid, and brittle with
high melting points. Why metals such as alloy, gold or iron The bond order is the number of
dent and bent rather than crack like electron pairs being shared by a given
Ionic compounds do not conduct rocks, coal or glass when applied force
electricity in the solid state. pair of atoms.
on them? The bond energy (BE) is the energy
Ionic compounds conduct electricity needed to overcome the attraction
when melted or dissolved. The iron ions can move within the sea of between the nuclei and the shared
electrons around them. electrons. The stronger the bond the
Why ionic compounds like salt
(NaCl) crack? They can shift a little closer together or higher the bond energy.
farther apart without breaking the The bond length is the distance
Before the force is applied the metallic bonds between them. between the nuclei of the bonded
crystal has a uniform platform of
Therefore, the metal can bend rather than atoms.
ions. crack when applied force on them.
If the applied force is strong Why does water volume expand
enough, it pushes the ions out of REFERENCES: when it freezes?

alignment. Foundation, C. (n.d.). 12 Foundation. Retrieved December 26, 2020, from During freezing, water molecules lose
A repulsive force created by https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-science- energy and do not vibrate or move
nearby like-charged ions breaks around as vigorously.
flexbook-2.0/section/5.10/primary/lesson/metallic-bonding-ms-ps
apart the crystal. As water freezes the hydrogen bonds
Intermediate, C. (n.d.). Chemistry for Non-Majors. Retrieved December 26, push the H20 molecules farther apart
2020, from
from each other increasing the
https://courses.lumenlearning.com/cheminter/chapter/coordination- intermolecular space resulting in
numbers/
expansion.
Why does water expand when it freezes? (n.d.). Retrieved December 26,
2020, from https://www.thenakedscientists.com/articles/questions/why-

does-water-expand-when-it-freezes

Muhammad sukriyllah yus

01 why ionic compounds like salt 0
nacl crack
Ionic crystals are hard because of tight
packing lattices, say, the positive and negative
ions are strongly attached among themselves

So, if mechanical pressure is applied to an
ionic crystal then ions of similar charges may be
forced to get closer to each other.

Now, by doing so, the electrostatic repulsion
can be enough to split or disorient completely
the lattice infrastructure. Thus imparting the
brittle character.

04 References

1)https://chemistry.stackexchange.com/questions/33
322/why-are-so-many-ionic-compounds-brittle/
2)https://en.m.wikibooks.org/wiki/Structural_Bioche
mistry/Unique_Properties/Expansion_upon_Freezing
3)https://www.ck12.org/chemistry/metallic-
bond/lesson/Metallic-Bonding-MS-PS/

sri (s52436)

02 why does water volume expand when it freezes

When frozen, water molecules take a more defined
shape and arrange themselves in six-sided
crystalline structures. The crystalline
arrangement is less dense than that of the molecules
in liquid form which makes the ice less dense than
the liquid water. Thus water expands as it freezes,
and ice floats atop water.

03 Why metals such an alloy, gold or iron dent and bend
rather than crack like rocks, coal or glass when
applied force?

Metallic bonds are the force of attraction between
positive metal ions and the valence electrons that
are constantly moving around them. The ions form a
lattice-like structure held together by the metallic
bonds.

Metallic bonds explain why metals can conduct
electricity and bend without breaking.

FIZ4107: Atomic Physics

FIZ4107
ASSIGNMENT 1

Prepared by: Muhammad Aimi
Asyraf bin Ahmad (S5750)

WHY IONIC Ionic Bond
COMPOUNDS
CRACK? Ionic bond has strong ionic bond, which makes it
hard. However, when enough force is applied to
it, the arrangement of the ion change such that
like charges will be placed next to each other.
The ions repel each other, which cause the
compund to crack.

WHY DOES Hydrogen Bond
WATER
VOLUME Water molecules lose energy and the bonds becomes
EXPAND easier to break causing more stable hydrogen-bonds to
WHEN IT form between water molecules. The average H-bonds per
FREEZES? water molecule is much closer to its maximum due to the
crystal lattice structure imposed on water molecules once
the freezing point is reached,. The orderly, crystalline way in
which the hydrogen-bonds form causes density to
decrease because each water molecule is held away from
its neighbors at a distance equal to the length of the
hydrogen bonds.

WHY Metallic Bond
METALS
BEND In metallic bonds, electrons move freely among
RATHER the atomic nuclei—they are delocalized and
THAN move within the "sea" of electrons, so there isn’t
CRACK? a definitive bond in the way molecular and ionic
bonds form. When stress is applied, the
electrons simply slip over to an adjacent nucleus
without breaking their bond.

REFERENCES:
1.PHYSICAL PROPERTIES OF IONIC COMPOUNDS | CHEMISTRY FOR NON-MAJORS. (N.D.). RETRIEVED
DECEMBER 28, 2020, FROM
HTTPS://COURSES.LUMENLEARNING.COM/CHEMINTER/CHAPTER/COORDINATION-NUMBERS/
2.STRUCTURAL BIOCHEMISTRY/UNIQUE PROPERTIES/EXPANSION UPON FREEZING - WIKIBOOKS, OPEN
BOOKS FOR AN OPEN WORLD. (N.D.). RETRIEVED DECEMBER 28, 2020, FROM
HTTPS://EN.WIKIBOOKS.ORG/WIKI/STRUCTURAL_BIOCHEMISTRY/UNIQUE_PROPERTIES/EXPANSION_U
PON_FREEZING
3.RODRIGUEZ, J. A., & GOODMAN, D. W. (1992). THE NATURE OF THE METAL-METAL BOND IN BIMETALLIC
SURFACES. SCIENCE, 257(5072). HTTPS://DOI.ORG/10.1126/SCIENCE.257.5072.897

Muhammad Alif bin Kamarul Azman
(S54062)

Why ionic compounds like salt(NaCl) crack? Why does water volume expand when

-+- - As water freezes the it freezes?
++ - molecules formed a stable
+-+ --+ hexagonal crystal from an
unstable and irregularly
+- formed hydrogen bonds.

As force is applied, the ions O-
were repositioned the like-
charged ions next to each other.
-+-
- O-
Opposite charge ion forms
an electrostatic force that
holds the particles together
in salt compound.

The hexagonal arranged+ O-
molecules increased
the intermolecular

- space resulting to
expansion of volume

- + O O- O-Rreepaspuualslrtiitvn.egftohrecWecriyshsptyarolmdtoucbeerteaaklss such as alloy, gold, or iron dent
and bend rather than crack likerocks, coal, or
glass when applied force on them?

+++ +++ +++
+++ +++
+++
Metals are formed by
metallic bond with fix Since, the electrons were attracted towards
cation and surrounded by a several nucleus, it forms a strong non-
sea of electron directional bond which holds the molecule
together even when force is applied

Jekyll1911. (2020, February 21). Why Are Salt Crystals Brittle?
Retrieved December 27, 2020, from
https://expandusceramics.com/qa/why-are-salt-crystals-
brittle.html
Water (Its Volume Expansion Upon Freezing). (n.d.). Retrieved
December 27, 2020, from https://www.e-
education.psu.edu/matse81/node/2119
Brainard, J. (2020, May 18). Metallic Bond. Retrieved December
27, 2020, from https://www.ck12.org/chemistry/metallic-
bond/lesson/Metallic-Bonding-MS-PS/

IMAN SYAKIR BIN IBRAHIM FIZ4107 ATOMIC
S54112 PHYSICS

WHY IONIC COMPOUND WHY DOES WATER VOLUME
LIKE SALT(NACL) CRACK ? EXPAND WHEN IT FREEZES ?

Before the exteral force is applied, When ice molecules freeze, it will
the salt (NaCL) is arranged in a defined as shape and form a six-
uniform ions. sided crystalline structures which
When the external force is applied, is tightly packed between each
it will rearranged the particles other
then force the ions out of the After the water is cooled, it liquid
uniform arragement. water turn to solid form. This is
The applied force will cause the less dense than liquid form
repulsive force breaks apart the Then, it will expend slightlu until
salt and make it crack. reached the freezing point.
The water molecule definitely can
expand by approximately 9%.

ICE WATER

WHY METALS SUCH AS ALLOY,GOLD OR IRON DENT AND BEND
RATHER THAN CRACK LIKE ROCKY COAL AND GLASS WHEN
APPLIED FORCE ON THEM ?

Atoms in metal obviously packed in crystal likes structure and make

them quite flexible

Valence electron of each atoms atracted with nucleus of other atoms

Electron will spread among atoms and form electron sea and make the

ion able to move

Since the bond of the atom shared by many atoms it will make the

metallic bonding will be non-directional. electron sea
So, the metal ions can be far and close without breaking the metallic surround the
bond.

It will result the metal bend when external force is applied on it. +ve ions

REFERENCES
Metwalli, K. (2017, March 16). Ionic bonds and Ionic compounds. Retrieved December 27, 2020, from
https://www.slideshare.net/KamalMetwalli/ionic-bonds-and-ionic-compounds
Structural Biochemistry/Unique Properties/Expansion upon Freezing. (n.d.). Retrieved December 27, 2020, from
https://en.wikibooks.org/wiki/Structural_Biochemistry/Unique_Properties/Expansion_upon_Freezing
Why does water expand when it freezes? Why does liquid water have a density maximum? (n.d.). Retrieved December 27,
2020, from http://www.iapws.org/faq1/freeze.html

ABDULLAH HARITH (S54276) FIZIK ATOM

Why ionic compounds like NaCl crack?

Force When ion of the same charged ion next to
each other, the ionic compounds repels
Crystal breaks
apart

Why does water expand when frozen?

Water At low temperature, water molecules
takes a more defined shape and arranged

in - sided crystalline structure

Stable
hydrogen bond

Why metals such as alloys, gold, and iron dent or bent
rather than cracks when force is applied?

Force electron attracted to nucleus forming
strong non-directional bonds while
Metals are formed with fixed cation maintaining the molecule together even
and surrounded by a sea of
electron when force present

Muhammad Yazid bin AATTOOMMIICC PPHHYYSSIICCSS
Mohamad Yasin
S54420
FIZ4107

Why ionic compound crack?

When force applied to salt, the crystal structure of the salt due to force applied has changed
the position fo the ion one another.

Ionic compound made up of strong bond between
the positive and negative ions which forms rigid
crystalline structures, lattice structure. But it
requires a lot of energy to break the bond apart
from each other!!!

Water volumes expend when freeze? Water start to freeze at 0° C!!!

Water molecules consist of one oxygen atom Hexagonal
negatively charged and two hydrogen bond shaped and
positively charged, resulting in the forming of stable hydrogen
hydrogen bond. The hydrogen bonds push the
water molecules farther apart and increase the bonds.
intermolecular space and changing into a stable
hexagonal lattice structure. Ice that has been
freeze becomes less dense than water and they
that is why they afloat on top of water.

No regular shape
and unstable

hydrogen bonds.

Why metal bends rather than crack?

Metals such as alloy, gold, and iron Sea of electrons allows the metal ions Metallic bonds required all the metal atoms to
can easily be made into shaped to slide past each other when force share their valence electrons with delocalized
without crack due to sea of electron. applied without breaking the bonds.
bonds to retain the structure.

Reference

Staff Writer. (2020, March 31). Why Are Ionic Compounds
Brittle? Retrieved December 27, 2020, from
https://www.reference.com/science/ionic-compounds-brittle-
bdb2aaae41b8758

Water Expansion When Freezing. (2020, October 29). Retrieved
December 27, 2020, from
https://www.sciencefacts.net/why-does-water-expand-when-it-
freezes.html

Why are metals malleable?: Socratic. (2014, March 26).
Retrieved December 27, 2020, from
https://socratic.org/questions/why-are-metals-malleable

Lecture note Topic 4.

S54660

Topic 4 : Molecules and Energy BondfileMuhammad Irfan Hazim bin mowardi

Why ionic Typically, when undisturbed salt ions are
arranged uniformly with each other.
compund like
However, when a strong force is applied to
( )salt NaCL the ionic compound, the strong force will
?crack realign the arrangement of ions in the
compound.

As the ions are moved out of the original
allignment, the force of repulsion will
break the crystal apart. This causes the salt
to crack.

In liquid state, water molecules (forming Why does
and breaking hydrogen bonds) travel
continuously, resulting in less expansion. water

Water molecules take a more defined form volume
when frozen and organize themselves in
crystalline six-sided structures. expand when

?it freezes

In liquid form, the crystalline structure is less compact than that of the
molecules, rendering the ice less dense than liquid water. The volume
expands by approximately 9% as water freezes.

Why metals such Metals are malleable - without
splitting, they can be bent and
,as alloy gold or shaped. This is because they are
layers of atoms that, when the metal
iron dent and is bent, pounded or pressed, will slip
over each other.
bend rather than Metals form giant structures in which electrons are free to travel in the
outer shells of the metal atoms. For these free electrons and metal ions,
,crack like rock the metallic bond is the force of attraction. Metallic bonds are solid, so a
normal structure can be sustained by metals and usually have high
coal or glass melting and boiling points.

when applied

?forces on them

References

Brainard, J. (2020, May 18) Metallic Bond. Retrieved December 25, 2020, from https://www.ck12.org/chemistry/metallic-bond/lesson/Metallic-Bonding-MS-PS/
Structural Biochemistry/Unique Properties/Expansion upon Freezin, (n.d.). Retrieved 26 December, 2020 from
https://en.wikibooks.org/wiki/Structural_Biochemistry/Unique_Properties/Expansion_upon_Freezing
Metwalli, K. (2017, March 16) Ionic bonds and ionic compounds. retrieved December 25, 2020, from https://www.slideshare.net/KamalMetwalli/ionic-bonds-and-
ionic-compounds#:~:text=What%20makes%20the%20crystal%20cracks,force%20breaks%20apart%20the%20crystal.





TOPICS 4: MOLECULES & ENERGY
BONDFILE

WHY IONIC COMPOUNDS LIKE SALT (NACL) CRACK?

The ionic compound like salt (NaCl) breaks apart because
the applied force repositions the like-charged ions next to
1 each other.
It then resulting repulsive force breaks apart the crystal.

WHY DOES WATER VOLUME EXPAND WHEN IT FREEZES?

When frozen, water molecules take a more defined shape

2 and arrange themselves in six-sided crystalline structures.
The crystalline arrangement is less dense than that of the

molecules in liquid form which makes the ice less dense

than the liquid water.

When water freezes, the volume expands by

approximately 9%.

WHY METALS SUCH AS ALLOY, GOLD, OR IRON DENT AND BEND RATHER

THAN CRACK LIKE ROCKS, COAL, OR GLASS WHEN APPLIED FORCE ON

3 THEM?

The lattice-like structure of metal ions is strong but quite

flexible.

This allows metals to bend without breaking.

The iron ions can move within the “sea” of electrons

around them.

They can shift a little closer together or farther apart

without breaking the metallic bonds between them.

Therefore, the metal can bend rather than crack when

applied force on them.

References:

Brainard, J. (2020, May 18). Metallic Bond. Retrieved December 27, 2020, from https://www.ck12.org/chemistry/metallic-
bond/lesson/Metallic-Bonding-MS-PS/
Structural Biochemistry/Unique Properties/Expansion upon Freezing. (n.d.). Retrieved December 27, 2020, from
https://en.wikibooks.org/wiki/Structural_Biochemistry/Unique_Properties/Expansion_upon_Freezing
Metwalli, K. (2017, March 16). Ionic bonds and Ionic compounds. Retrieved December 27, 2020, from
https://www.slideshare.net/KamalMetwalli/ionic-bonds-and-ionic-compounds

MOHAMAD FAIQ HAZIQ BIN HAMDAN

S55899

Energy Molecule Bonds.

1) Why ionic compound like salt (NaCl) crack?
Ionic compound like salt crack because of huge
mechanical forces like hit the salt with hammer to
force a layer of ions to move relative to its
neighbour. When the move occur, it brings the ions of
equal charge next to one another.

2) Why does water volume expand when it freezes?
Water is in liquid state which its molecules move freely
with minimum interference. When water in solid state, thr
molecules starts to form a crystalline shaped. Water consist
of an oxygen and two hydrogen atoms that can be a curve
slightly as a very wide V shape. Hence, water that frozen
expand and involve more volume than water that in liquid
state.

3) Why metals such as alloy, gold, or iron dent and bend rather
than crack rocks, coal, glass when applied force on them?

Metals are malleable which are can be bent and shaped when
applied force on them without crack. This is because metals
are contains the atom layers that can slide to each other when
hammered or pressed. Metal have metallic bond which is strong
bond that can keep the regular structure of the metal.

References Nurul Nasuha Binti Mohd Rosdi
S56101
1) Chemistry for Non - Majors.
https://courses.lumenlearning.com/cheminter
/chapter/coordination-numbers/

2) Why does volume of water increase
after freezing?.
https://www.quora.com/Why-does-volume
-of-water-increase-after-freezing

3) Metals - Iron and aluminium - GCSE Chemistry
(Single Science) Revision - Other - BBC Bitesize.
https://www.bbc.co.uk/bitesize/guides/zpcdsg8
/revision/1

Chapter 4 :

Molecules Bond Energy
Assignment 1

LEONG GIA XING S56469

1. Why ionic compounds 2. Why does water volume
like salt (NaCl) crack? expand when it freezes?

Ionic bond is the electrostatic force When frozen, water molecules take a more
that holds oppositely charged defined shape and arrange themselves in six-
particles together in an ionic sided crystalline structures. The crystalline
compound. arrangement is less dense than that of the
Ionic compound in the solid state are molecules in liquid form which makes the ice
locked into fixed positions by strong less dense than the liquid water. Thus water
attractive forces. expands as it freezes, and ice floats stop water.
When applied force realign particles
is strong enough, it pushes the ions
out of alignment. The forces of
repulsion break NaCl apart, and the
repulsive force created by nearby
like-charged ions break apart from
the NaCl.

3. Why metals such as alloy, gold or iron dent and bent
rather than crack like rocks,coal, or glass when applied
force on them?

Metals such as alloy, gold or iron is metallic bonds are forces of attraction between positive metal ions and
the valence electrons that are constantly moving around them.
The valence electrons of metals move freely in this way because metals have relatively low electronegativity
or attraction to electrons.
Metal ions can move within the “sea” of electrons around them. They can shift a little closer together or
farther apart without breaking the metallic bonds between them. Therefore, the metal can bend rather
than crack when applied force on them.

Reference :

Molecular Metal-Metal Bonds: Compounds, Synthesis, Propertiesedited by Stephen T. Liddle
Atomic Charges, Bond Properties, and Molecular Energies By Sandor Fliszar
Chemical Structure and Bonding By Roger L. DeKock, Harry B. Gray

ASSIGNMENT 1 EVON CHIENG HUI NGIIK

(TOPIC 4) S56796
FIZ 4107 FIZIK ATOM

Q: Why Ionic compounds like salt
(NaCl) crack?

A: The applied force repositions the liked-charged
ions of the Ionic compound next to each other.

Q: Why does water volume expand
when it freezes?

A: Water molecule is held together by Hydrogen
bonds. Therefore, when the temperature

decreases, the bonds align is such a way that the
volume of water get increases when frozen

Q: Why metals such as alloy, gold, or iron
dent and bend rather than crack like
rocks, coal, or glass when applied
force on them?

A: The ions can move within the "sea" of electrons
around them. Hence, they can shift a little closer
together or further apart without breaking the
metallic bonds between them. Therefore, metal can

bend rather than crack

1. Jean Brainard,
P. (2016, August 25th). https://www.ck12.org/student/. Retrieved from
Metallic Bonding:

https://www.saultschools.org/cms/lib/MI17000143/Centricity/Domain/222/M
etallic%20Bonding%20Reading%20Assignment.pdf

2. Kumar, K.
(2018, August 9th). Research Gate. Retrieved from Why is the volume of
water increasing when it is freezing?:
https://www.researchgate.net/post/Why-is-the-volume-of-water-increasing-
when-it-is-freezing
3. Metwalli, K.
(2017, March 16th). SlideShare. Retrieved from Ionic bonds and Ionic
compounds: https://www.slideshare.net/KamalMetwalli/ionic-bonds-and-
ionic-compounds



MUSTOFA BIN HOSEN Ionic compound(NaCI)
S56816 Crack?

HY? Water volume expands when
freezes?

Metal dent and bend rather
than crack when applied
force?

W When frozen, Metallic bonds allow
hydrogen bonds are positive metal ions
Applied force on formed that makes
the ionic molecules make a and the valence
shape and volumes electrons that are
compound, it constantly moving
causes a expand by around them when
repulsion. approximately 9%.
applied a force.

Metallic Bond

Hydrogen Bond

Repulsion

Website https://expandusceramics.com https://www.ck12.org/chemist https://en.wikibooks.org/wiki/Structu
Reference /qa/why-are-salt-crystals- ry/metallic- ral_Biochemistry/Unique_Properties/E
xpansion_upon_Freezing#:~:text=Whe
brittle.html#:~:text=Ionic%20c bond/lesson/Metallic-Bonding- n%20frozen%2C%20water%20molecul
ompounds%20are%20brittle% MS- es%20take,dense%20than%20the%20l
20due,that%20make%20up%2 iquid%20water.&text=Thus%20water
PS/#:~:text=A%3A%20The%20i %20expands%20as%20it%20freezes%2
0the%20molecules. ron%20ions%20can,when%20t C%20and%20ice%20floats%20atop%2
he%20hammer%20hits%20it.
0water.



FIZ4107
FIZIK ATOM
ASSIGNMENT 1

Name: Chong Mun Fei
Matrix: S59150

Programme: Financial Mathematics

Question 1:
Why ionic compound like salt (NaCl) crack?

When external force is acted on the ionic compound, the atom of the
ionic compound will slide away from its original position. It will cause
the charge between two atoms same and repel from each other.
Then, the crystal will crack.

Question 2:
Why does water volume expand when it freezes?

When water freezes, the molecules form a network of hydrogen
bonds or a process called hydrogen bonding. These hydrogen bonds
have a unique structure where in two oxygen atoms and one
hydrogen atom form one line. Although the frozen water is
considered as solidified, it also has a very open crystalline structure
with a lot of spaces inside, making it less dense than most solids, and
even some liquids such as liquid water. Because of this crystalline
structure that after reaching its freezing point, water expands by
about nine percent.

Question 3:

Why metals such as alloy, gold, or iron dent and bend rather crack
like rock, coal, or glass when applied force on them?

Atom of metal are arranged tidily in layer. The atom can easily slide
over each other while external force acted on it. The metal will
deform. So, metal will dent and bent rather crack when applied
force on it





Name : Lam Jing Kit Ionic Structure
Matrics N.O. : S59387
Form by accept & donate of electron between ion
Example of ionic structure when External forces acted , they shattered.
crack. Causes change in displacement of layer of ions ,
like-charge ions align together and repel each
other.
Repel causes ionic component crack

Water Structure Example of water structure in solid
state.
Water form hydrogen bonds.
In liquid state , water molecules move freely.
While freezing , the water molecule will lose
energy, and form a hexagon structure molecules
It causes the space between water molecules
increase . Hence volume of ice is larger .

Example of metal structure after Metal Structure
external forces acted on it
Metallic bond form by donate valance electrons of
metal atoms to form "sea of delocalize" electron.
The metal molecules are hold by bonding to the
electrons
When external forces act on it , the layer of metal
molecules are slide over one another.
It will not break because still held by the sea of
electrons. Metal is change in shape like bend only.

References :

1.Yip , P(2018) . PRE-U STPM Text CHEMISTRY . Selangor , Malaysia: Penerbitan Pelangi Sdn.Bhd.
2.Clark . J (16 August 2020 ) . Metallic Bonding . Retrieve from

https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_an
d_Theoretical_Chemistry)/Chemical_Bonding/Fundamentals_of_Chemical_Bonding/Metallic_Bonding