Assignment SK015

Title: Assignment
SK15 Periodic Table

Name: 15_Nur Syamimi binti Abd Sharif
Matrice Number: MS2217112985

IC Number: 040724-08-0576
Class: M6T24

Lecturer: Madam Kong Suet Lee
Digital Platform Link:



(i) Atomic radius
(ii) Ionic radius
(iii) Ionisation energy
(iv) Electronegativity
(v) Elements in group
(vi) Elements in period

ATOMIC RADIUS

ACROSS A PERIOD DOWN A GROUP
- Number of protons increase - Principal quantum number, n of the
because more protons are added to the
nucleus, hence nuclear charge also increase valence electrons increase
- Effecive nuclear charge increase - more inner electrons and inner shells.
- inner electrons shield the outer electrons
significantly. effectively. Screening effect increase.
- Outer electrons are pulled closer to nucleus. - Valence electrons are attracted weaker

Force of attraction or nucleus-electron and further away from the nucleus.
attraction increases. -Atomic radius generally increase in a
group from top to bottom. Hence the force
- Atomic radius becomes smaller.
- Atomic radius generally decrease across a of attraction
- The effective nuclear charge, Zeff for
period from left to right. elements in the same group is constant

ATOMIC RADIUS

ANALYSIS

Sodium and potassium Magnisium, aluminium and chlorine
( going down group 1 ) (across period 3)

-The principal quantum number of Na is 3 , less - Proton number of Mg is 12 , Al is 13 and Cl is 17.

than K that have 4 principle quantum number. That’s means Cl have biggest proton number than Al

-That means K have more inner electrons and inner and Mg.

shells than Na. - More protons are added to the nucleus of Cl, hence

- Screening effect of K is MORE than Na . nuclear charge of Cl is more than Al and Mg.

- Valence electrons of K are attracted weaker and - Effecive nuclear charge of Cl is larger than Al and

further away from the nucleus. Mg.
-In conclusion, K have atomic radius bigger than Na. -Cl have force of attraction or nucleus-electron

attraction that bigger than Al and Mg.

- Thus, atomic radius of Cl become smaller than Mg

and Al.

CATION ( POSITIVE IONS ) IONIC RADIUS

ANION ( NEGATIVE IONS )

• Cation are smaller than their neutral atoms. • Anion are always larger than their neutral atoms.
• When electrons are removed from an atom, • Has more electrons as it gains electron during its

repulsion between electrons decrease. formation.
• Number of proton remain and nuclear charge • When electrons are added to an atom, repulsion

remain the same. between electrons increase
• Remaining electrons are pulled closer towards • That can caused its to spread out & experienced

the nucleus. less attraction from the nucleus
• Electron cloud shrink. • Furthermore, outer orbital expands, nuclear
• Cation is smaller than its atom.
charge remain the same
• Electrons cloud enlarge
• Anions is larger than its atom

IONIC RADIUS

Analysis

ACROSS PERIOD 3

• Ionic radii of cations Mg+ is bigger than Al3+
• Metal (Mg and Al) forming cations which are

isoelectronic as the metals lose their outer
electrons.
• The proton number and effective nuclear charge
Mg is less than Al and causes the ionic radius Mg
is higher than Al.
• Non-metal (Cl) forming anions which are
isoelectronic as the non-metals gain electrons.

CATION VS ATOM IONIC RADIUS

ANION VS ATOM

Positive ions are smaller than the atoms they come from. Negative ions are bigger than the atoms they come from.

Na is 1s^2 2s^2 2p^6 3s^1 Cl is 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2

Na+ is 1s^2 2s^2 2p^6. Cl- is 1s^2 2s^2 2p^6 3s^2 3p^6

You've lost a whole layer of electrons, and the remaining • Although the electrons are still all in the 3-level, the

10 electrons are being pulled in by the full force of 11 extra repulsion produced by the incoming electron

protons. causes the atom to expand.

• There are still only 17 protons, but they are now

having to hold 18 electrons.

Ionisation Energy (IE)

THE IONISATION ENERGY
• The minimum energy required to remove an electron from a gaseous atom or ion in tis ground sate.

THE FIRST IONISATION ENERGY
• The minimum energy required to remove on electron from the outermost orbital of a neutral gaseous atom in its ground state.
• Example :

Na (g)  Na+ (g) + e

THE SECOND IONISATION ENERGY
• The energy required to remove one electron from a positive gaseous ion in its ground state.
• Example :

Na+ (g)  Na2+ (g) + e

FACTORS AFFECTING THE IONISATION ENERGY

ATOMIC RADIUS EFFECTIVE NUCLEAR CHARGE (Zeff) SHIELDING EFFECT

The valence electrons of an atom with The higher the effective nuclear charge, the The shielding effect of the electrons of the
larger radius experience a less atraction
towards nucleus, hence possesses a low stronger the attraction forces between the inner shells causes the outer electrons to
ionisation energy.
nucleus and eletrons. This causes the be less attracted to the nucleus and thus

ionisation energy to increase decrease the magnitude of ionisation

energy.

Ionisation Energy (IE)

When moving across a period When going down a group

• Effective nuclear charge increase causes the • Number of shell increase, the shielding effect

size of the atoms to decrease increase, atomic size also increase.
• Valence electrons are closer to the nucleus • Valence electrons are farther away from the
• Attractions between the nucleus and the
nucleus and held less tightly by the nucleus.
valence electrons are stronger • Attractions between the nucleus and the
• More difficult to remove an electrons from
valence electrons are weaker.
each atom • Easier to remove an electron from each atom.
• More energy is needed to remove the • So, less energy is needed to remove the first

outermost electron from an atom electron.
• Thus, ionisation energy (IE) increase. • Thus, ionisation energy decrease.
• In general, IE increases from left to right.

Ionisation Energy (IE) Down a group

Across a period ANALYSIS

ALUMINIUM & CHLORINE SODIUM & POTASSIUM

Effective nuclear charge of Cl is bigger then Al Number of shell and the shielding effect for K is
causes the size of the atoms of Cl is smaller than Al. higher than Na, atomic size for K is bigger than Na.

Cl have valence electrons that are closer to the Valence electrons of K are farther away from the
nucleus than Al. nucleus than Na.

So ,attractions between the nucleus and the valence So, attractions between the nucleus and the valence

electrons of Cl are stronger than Al. electrons of K are less than Na.

More difficult to remove an electrons from each Easier to remove an electron from each atom and
atom and more energy is needed to remove the less energy is needed to remove the outermost
outermost electron from an atom electron from an atom for K than Na.
for Cl than Al.

Thus, ionisation energy for Cl is higher than Al. Thus, ionisation energy for K is less than Na.

PROBLEM MAGNISIUM ALUMINIUM

IDENTIFICATION Mg (g) -------------- Mg+ (g) + e Al ( g ) --------------- Al+(g) + e

Anomalous cases 1s^2 2s^2 2p^6 3s^2 1s^2 2s^2 2p^6 3s^1 1s^2 2s^2 2p^6 3s^2 3p^1 1s^2 2s^2 2p^6 3s^2
for Mg and Al
Electronic configurations: Electronic configurations:
Magnesium: 1s2 2s2 2p6 3s2 Aluminium: 1s2 2s2 2p6 3s2 3p1

The electron in the 3s orbital of Mg is at lower energy The electron in the 3p orbital of Al is at higher energy

level than 3p electron Al level than 3s electron Mg

Attraction of nucleus towards the 3s electron in Mg is Attraction of nucleus towards the 3p electron in Al is

stronger weaker

Ionisation energy of Mg is higher than Al Ionisation energy of Al is lower than Mg

FIRST (IE) OF PERIOD 3 More energy is required to remove electron from a full-filled 3s orbital in Mg which is more stable.
ELEMENT So, Mg has higher first ionization energy than Al

ELECTRONEGATIVITIES OF ELEMENTS

Across a period Down a group

• Proton number increase, nucleus charge • Although the positive charge on the nucleus
become more positive, effective nuclear
charge, Zeff increase. increases, this is more than the offset by the

• So, atomic radius decreases (atomic size increase in the atomic radius and the
become smaller).
additional screening effect of the extra
• Attraction between nucleus and outer
electron become stronger. electron shells.
• So, going down a group, number of shell
• Hence, the atom has greater relative
tendency to attract electron to itself. increase, the atomic size increase because

• Therefore when across a period, the the screening effect increases.
electronegativity increases. • The attraction of the nucleus and outer

electron become weaker.
• Hence, the atom has smaller relative

tendency to attract electron to itself.
• Therefore when going down a group, the

electronegativity decreases.

ELECTRONEGATIVITIES OF ELEMENTS

ANALYSIS

DOWN A GROUP ACROSS A PERIOD

Number of shell K is higher than Na, then K have Cl have higher proton number than Al, thus effective

bigger atomic size than Na because the screening nuclear charge, Zeff of Cl is higher than Al.

effect for K is higher than Na

So, K have less attraction of the nucleus and outer So, atomic radius for Cl is smaller than Al because Cl

electron than Na. have higher attraction between nucleus and outer

electron than Al .

Hence, atom K has smaller relative tendency to Hence, atom Cl has greater relative tendency to
attract electron to itself than atom Na. attract electron to itself than atom Al.

Therefore the electronegativity of K is lower than Therefore, the electronegativity Cl is higher than Al.
Na.

ELEMENT IN GROUP

ELEMENTS ELECTRON GROUP VALENCE ELECTRON PROTON BLOCK EXPLAINATION
SODIUM
POTASSIUM CONFIGURATION NUMBER` • The group in periodic table are
MAGNISIUM numbered from 1 to 18
ALUMINIUM 1s^2 2s^2 2p^6 1 1 11 s-block
CHLORINE 3s^1

1s^2 2s^2 2p^6 1 1 19 s-block • Element in the same group have
3s^2 3p^6 4s^1 2 the same number of valence
3 electrons
1s^2 2s^2 2p^6 2 7
3s^2 12 s-block • For example, element that have
2 valence electron is from group
1s^2 2s^2 2p^6 13 2
3s^2 3p^1
13 p-block • Group number = number of
1s^2 2s^2 2p^6 17 valence electron,if the element
3s^2 3p^5 is in block s and d

17 p-block • Group number = number of
valence electron + 10 , if the
element is in block p

ANALYSIS

ELEMENTS GROUP VALENCE EXPLAINATION
SODIUM 1 ELECTRON
POTASSIUM 1
MAGNISIUM 1 Sodium have only one valence electron in their highest-energy orbital (3s^1) ,
ALUMINIUM Therefore, Na is in group 1

CHLORINE 1 Potassium have only one valence electron in their highest-energy orbital (4s^1) ,
Therefore, K is in group 1

2 2 Magnisium have only two valence electron in their highest-energy orbital (3s^2) ,
Therefore, Mg is in group 2

13 3 Aluminium have three electrons in the outermost shell which are a full s orbital and
one electron in p orbital with the valence electron configuration (3s^2 3p^1) .
Number of valence electron + 10, if the element is in block p which make 3 +10
=13. Therefore, Al is in group 13

17 7 Chlorine have three electrons in the outermost shell which are a full s orbital and
five electron in p orbital with the valence electron configuration (3s^2 3p^5) .
Number of valence electron + 10, if the element is in block p which make 7 +10
=17. Therefore, Cl is in group 17

ELEMENT IN PERIOD

ELEMENTS ELECTRON PERIOD BLOCK EXPLAINATION
SODIUM
CONFIGURATION s-block • Periods are the horizontal rows of the periodic table.
• The period in periodic table are numbered from 1 to 7
1s^2 2s^2 2p^6 3
3s^1

POTASSIUM 1s^2 2s^2 2p^6 4 s-block • Element in the same period have the same principle

3s^2 3p^6 4s^1 quantum number of the electrons in valence shell

MAGNISIUM 1s^2 2s^2 2p^6 3 s-block • For example, element that have the principle quantum
3s^2 number of electrons in valence elelctron ,n=3 meaning

the element is period 3

ALUMINIUM 1s^2 2s^2 2p^6 3 p-block • Period number = principle quantum number, n, of the

3s^2 3p^1 electrons in valence electron

CHLORINE 1s^2 2s^2 2p^6 3 p-block

3s^2 3p^5

ELEMENTS ANALYSIS
SODIUM
POTASSIUM PERIOD EXPLAINATION

3 The highest principle quantum number,n of the electron in valence shell
in element Na is three (3s^1) , Therefore, Na is in period 3

4 The highest principle quantum number,n of the electron in valence shell
in element K is four(4s^1) , Therefore, K is in period 4

MAGNISIUM 3 The highest principle quantum number,n of the electron in valence shell
ALUMINIUM in element Mg is three (3s^2) , Therefore, Mg is in period 3

3 The highest principle quantum number,n of the electron in valence shell
in element Al is three (3s^2 3p^5) .Therefore, Al is in period 3

CHLORINE 3 The highest principle quantum number,n of the electron in valence shell
in element Cl is three (3s^2 3p^5) . Therefore, Cl is in period 3

ELEMENT PERIODICITY OF THE PHYSICAL PROPERTIES OF ELEMENT

GROUP 1 METALLIC MELTING BOILING EXPLAINATION
SODIUM CHARACTER POINT POINT

POTASSIUM Lesser metallic 97.79 C 882.8 C • The metallic character of K is higher than Na because when going down group 1, screening
More metallic 63.5 C 759 C effect increase due to the number of electron shells increase. Thus atomic radius of K is bigger
than Na and ionization energy for K is less than Na. so K is easier to remove electrons from an
atom than Na.

• The melting point and boiling point for K is less than Na because the number of shell and
screening effect of K is higher than Na, then atomic radius of K is bigger than Na. so, the
outmost electron are futher from the nucleus causes the attraction between nucleus of the
atom and the electron in metallic bond of K is less than Na.

PERIOD 4 650 C 1120 C • The metallic character of Mg and Al are higher than Cl because when across period 3, effective
MAGNISIUM Metal 660 C 2450 C nuclear charge increase and the attraction between nucleus and valence electrons in valence
shell getting stronger. Thus atomic radius of Mg and Al are bigger than Cl and ionization energy
ALUMINIUM Metal for Mg and Al are lesser than Cl so it is difficult to remove electrons from an atom.

• The variation in melting point and boiling point of element Mg, Al and Cl caused by the
changes on structure and bonding of the elements across the period 3.

CHLORINE Non-metal -101 C -34 C • Mg  metallic structure and metallic bond
• Al  metallic structure and metallic bond
• Cl  simple molecular structure and covalent bond

APPLICATION

https://crosswordlabs.com/view/periodic-table-1427

CONCLUSION

One of the most significant contributions to the study of chemistry is the periodic table. It is full of
patterns that help us comprehend our surroundings more clearly. Many of the items and medicines
that we have today would not exist without it. The knowledge gathered from the periodic table can
open up a wide range of windows for understanding the entire universe in which we exist. I ought to
have a much deeper understanding of the periodic table after completing this activity.

Today's students and scientists can benefit from the table since it helps in identifying the kinds of
chemical reactions that a specific element is most likely to take part in. Students and scientists don't
need to memorise facts and statistics for each element instead, they can learn a lot about an
element's reactivity, potential of conducting electricity, hardness, and other properties by simply
looking at the table.Groups are made up of elements that are in the same column as one another
and have characteristics in common.

Periods are defined as elements that are present in the same row as one another and share the
same greatest level of unexcited electron energy. The fact that most periodic tables give you all the
information you need to balance a chemical reaction at a glance is another very valuable aspect of
the periodic table. Each element's atomic number and atomic weight are listed in the table. The
group of an element represents the actual charge of that element.

REFERENCE

WEBSITE
• Haynes,M. (2011). Melting points of the elements.

https://en.wikipedia.org/wiki/Melting_points_of_the_elements
• Clark,J.(Aug16,2020). Physical Properties of Period 3 Elements.

https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorg
anic_Chemistry)/Descriptive_Chemistry/Elements_Organized_by_Period/Period_3_Elements/Physical_Pro
perties_of_Period_3_Elements
• Liu, S. (2013).Physical properties.
http://chemicalperiodicity.pbworks.com/w/page/49244622/Ionic%20Radius
• Davis, L.(Aug 14, 2020)Electronic Structure of Elements.
https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Book%3A_Inorganic_Chemistry_(Saito)/01%
3A_Elements_and_Periodicity/1.03%3A_Electronic_Structure_of_Elements

BOOK
• Primo, L. (April 4th ,1995 ). Il sistema periodico.

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