Hewitt/Suchocki/Hewitt Conceptual Physical Science

Hewitt/Such

Conceptual Ph

Fourth

Chap
HOW ATOMS BOND

ATTR

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hocki/Hewitt

hysical Science

Edition

pter 15:
D AND MOLECULES
RACT

on-Wesley

This lecture w
unders

• Electron-Dot Structures
• The Formation of Ions
• Ionic Bonds
• Metallic Bonds
• Covalent Bonds
• Polar Covalent Bonds
• Molecular Polarity
• Molecular Attractions

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will help you
stand:

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Electron-Do

• Atoms bond together
electrons. To learn a
therefore, we need to
about how the electro
are organized.

• Electrons behave as
contained within a se
concentric shells.

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ot Structures

r through their
about bonding,
o know something
ons within an atom

though they are
eries of seven

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Electron-Do

The numbers indicate
the maximum number
of electrons each shell
may contain.

Note:

This is a “conceptual
model” and not a
representation of what
an atom “looks like.”

Rather, it helps us to
understand how the
electrons within atoms
behave.

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ot Structures

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The shells are more
easily drawn in two
dimensions.

Each atom has its own
configuration of
electrons. Elements in
the same group have
similar configurations,
which is why they have
similar properties.

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Electron-Do

• Valence electrons: Electro
of an atom. These are the
in chemical bonding.

• Electron-dot structure: A n
valence electrons surroun

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ot Structures

ons in the outermost shell
e ones that can participate
notation showing the
nding the atomic symbol.

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In class a

• Draw the dot diagram
chlorine ATOMS

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activity 1

m for sodium and

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Special

For heavier atoms, some v
available than others. Kryp
valence electrons, but only
shown within an electron-d
eight that extend farthest a

K

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l Note

valence electrons are more
pton, for example, has 18
y eight of these are typically
dot structure. These are the
away from the nucleus.

Kr

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Electron-Do

Note that elements with
the same electron-dot s

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ot Structures

hin the same group have
structure.

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Electron-Do
CHECK YOU

Sodium, Na, atomic number 1
electron. Upon losing this elec
periodic table does the sodium

A. Neon, Ne, atomic number 10
B. Magnesium, Mg, atomic numbe
C. Lithium, Li, atomic number 3
D. Sodium can only resemble sod

Explanation:
With 10 electrons, the sodium h
first and second shells, just like

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ot Structures
UR ANSWER

11, has only one valence
ctron, what other atom in the
m thus resemble?

er 12
dium.

has enough electrons to fill the
e neon, Ne.

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The Format

• Ion: An atom that has
more electrons.

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tion of Ions

s lost or gained one or

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The Format

• Ion: An atom that has
more electrons.

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tion of Ions

s lost or gained one or

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The Format

H
HO

Water

• Molecular ion: Typica
or gain of a hydrogen

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tion of Ions

H+

Hydrogen ion

ally formed by the loss
ion, H+.

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The Format

H
H O+

Hydronium ion,

• Molecular ion: Typica
or gain of a hydrogen

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tion of Ions

H

, H3O+

ally formed by the loss
ion, H+.

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Ionic B

• Ion: An atom that has
more electrons.

• Ionic Bond: The electr
between oppositely ch

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Bonds

s lost or gained one or
rical force of attraction
harged ions.

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In class a

• What is the charge o
from a magnesium a

• Why does it have this
charge?

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activity 2

of an ion that is formed
atom?

s sign and amount of

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Ionic B

• Ion: An atom that has
more electrons.

• Ionic Bond: The electr
between oppositely ch

Na+

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Bonds

s lost or gained one or

rical force of attraction
harged ions.

F-

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Ionic B

• Ion: An atom that has
more electrons.

• Ionic Bond: The electr
between oppositely ch

Na+

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Bonds

s lost or gained one or

rical force of attraction
harged ions.

F-

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In class a

• Draw the dot diagram
chlorine IONS

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activity 3

ms of sodium and

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Ionic B
CHECK YOU
What is the chemical formula f
aluminum ions, Al3+, and oxyg

A. AlO
B. Al3O2
C. Al2O3
D. Al6O6

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Bonds
UR ANSWER

for a compound made of
gen ions, O2–?

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Ionic B
CHECK YOU

What is the chemical formula f
magnesium ions, Mg2+, and ox

A. MgO
B. Mg2O2
C. Mg4O4
D. Any of the above

Explanation:
The chemical formula is used to sho
combine. By convention, the lowest
1:1 is used rather than 2:2. The num
when no subscript is written.

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Bonds
UR ANSWER

for a compound made of
xygen ions, O2–?

ow the ratio by which atoms
t numbers are preferred, so
meral 1, however, is implied

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In class a

• Is the change from so
physical or a chemica

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activity 4

odium and chlorine a
al change?

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In class a

• Write the chemical fo
compound calcium fl

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activity 5

ormula of the ionic
luoride

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Metallic

• Outer electrons in me
only weakly by the nu

• This weak attraction
to move about quite f

• This mobility of electr
many metallic proper

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c Bonds

etal atoms are held
ucleus.
allows the electrons
freely.
rons accounts for
rties.

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Metallic

• An alloy is a mixture

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c Bonds

of metallic elements.

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