Chemical Bonds

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Chemistry B11
Chapter 4 Chemical Bonds
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Chemical Bonds

• Ionic bonds
• 2. Covalent bonds
• 3. Metallic bonds
• 4. Hydrogen bonds
• 5. Van der Waals forces

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Chemical Bonds

• Ionic bonds
• 2. Covalent bonds

4
Review
Shell 1
Maximum 2 electrons in valence shell
Hydrogen and Helium
main-group elements 1A 8A
Other Shells
Maximum 8 electrons in valence shell
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Octet rule
Noble gases (Stable)
Goal of atoms
Filled valence shell
Ar 1s2 2s2 2p6 3s2 3p6
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Octet rule
Noble gases (Stable)
Goal of atoms
Filled valence shell
e-
Cl 1s2 2s2 2p6 3s2 3p5
Cl- 1s2 2s2 2p6 3s2 3p6
Ar 1s2 2s2 2p6 3s2 3p6
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Octet rule
Noble gases (Stable)
Goal of atoms
Filled valence shell
2e-
Mg 1s2 2s2 2p6 3s2
Mg 1s2 2s2 2p6
Ne 1s2 2s2 2p6
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Octet rule
Noble gases (Stable)
Goal of atoms
Filled valence shell
2e-
Mg 1s2 2s2 2p6 3s2
Mg 1s2 2s2 2p6
Ne 1s2 2s2 2p6
2e-
Ne 1s2 2s2 2p6
O 1s2 2s2 2p4
O2- 1s2 2s2 2p6
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Cation (Y)
Metals lose 1, 2 or 3 e-
Ions
Nonmetals gain 1, 2 or 3 e-
Anion (X-)
Number of protons and neutrons in the nucleus
remains unchanged.
Cation (Y) Na Li Ca2 Al3 Anion (X-)
Cl- F- O-2
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Two problems of Octet rule
1. Octet rule cannot be used for transition and
inner transition elements.
Fe2
Fe3
Cu1
Cu2
2. Ions of period 1 and 2 elements with charges
greater than 2 are unstable.
B3
B
C4
C4-
unstable
unstable
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Naming Monatomic Cations
International Union of Pure and Applied Chemistry
(IUPAC) systematic names
Name of the metal ion
H Hydrogen ion Li Lithium ion
Ca2 Calcium ion Al3 Aluminum ion
Cu1 Copper(I) ion Cu2 Copper(II) ion
Fe2 Iron(II) ion Fe3 Iron(III) ion
Sn2 Tin(II) ion Sn4 Tin(IV) ion
Hg Mercury(I) ion Hg2 Mercury(II) ion
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Naming Monatomic Cations
common name
-ous smaller charge
Name of the metal
-ic larger charge
Cu1 Copper(I) ion Cuprous ion Cu2 Copper(II)
ion Cupric ion
Hg Mercury(I) ion Mercurous ion Hg2 Mercury(II
) ion Mercuric ion
Fe2 Iron(II) ion Ferrous ion Fe3 Iron(III)
ion Ferric ion
Sn2 Tin(II) ion Stannous ion Sn4 Tin(IV)
ion Stannic ion
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Naming Monatomic Anions
Stem part of name -ide
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Naming Polyatomic Ions
Cation NH4 Ammonium
CN- Cyanide MnO4- Permanganate CrO42- Chromate
CO32- Carbonate HCO3- Hydrogen
Carbonate (bicarbonate) PO33- Phosphite PO43- P
hosphate HPO42- Hydrogen phosphate H2PO4- Dihyd
rogen phosphate
Anion
OH- Hydroxide NO2- Nitrite NO3- Nitrate SO32- S
ulfite SO42- Sulfate HSO3- Hydrogen
Sulfite (bisulfite) HSO4- Hydrogen
sulfate (bisulfate)
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Ionic bonds
Metal-Nonmetal
Cl 1s2 2s2 2p6 3s2 3p5
Na 1s2 2s2 2p6 3s1
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Sodium (Na)
NaCl
Chlorine (Cl)
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matter are neutral (uncharged) total number of
positive charges total number of negative
charges
Na
Cl-
NaCl
Ca2
Cl-
CaCl2
Al3
S2-
Al2S3
Ba2
O2-
Ba2O2
BaO
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matter are neutral (uncharged) total number of
positive charges total number of negative
charges
Na
NO3-
NaNO3
Ca2
CO32-
Ca2(CO3)2 Ca(CO3)
Al3
SO42-
Al2(SO4)3
Mg2
NO2-
Mg(NO2)2
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Naming Binary Ionic compounds
name of metal (cation) name of anion
NaCl sodium chloride CaO calcium oxide
Cu2O copper(I) oxide cuprous oxide CuO copper(II)
oxide cupric oxide
Naming Polyatomic Ionic compounds
BaCO3 barium carbonate Li2SO4 lithium
sulfate Li2SO3 lithium sulfite
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Covalent bonds
Nonmetal-Nonmetal Metalloid-Nonmetal
Sharing of valence electrons
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Lewis Dot Structure
He
Li
Al
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Electronegativity
A measure of an atoms attraction for the
electrons
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Covalent bonds
Nonpolar covalent bond electrons are shared
equally.
Polar covalent bond electrons are shared
unequally.
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Electronegativity bonds
H
H
2.1 2.1 0 Nonpolar covalent
N
H
3.0 2.1 0.9 polar covalent
Na
F
4.0 0.9 3.1 Ionic
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Covalent compounds
H
H

CH4
H C H
H C H

H
H
O
O
O
O



CH2O
H C H
H C H
H C H
H C H
Correct
H
H

NH3
H N H
H N H
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H
H
H
H
H C C
H
H C C
H
C2H4
H
H
H
H
C C
C C
H
H
H
H
Correct
H C C
H
H C C
H
C2H2
H C C H
H C C H
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Naming Binary Covalent compounds
Mono Di Tri Tetra Penta Hexa Hepta
Octa Nona Deca

• Dont use mono for the 1st element.
• Drop the a when followed by a vowel.

prefixes and name the less electronegative
element prefixed and the name the more
electronegative element ide
NO2 nitrogen dioxide N2O4 dinitrogen tetroxide
CCl4 carbon tetrachloride S2O3 disulfur trioxide
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VSEPR Model
VSEPR Valence-Shell Electron-Pair Repulsion
method
Bond angle angle between two atoms bonded to a
central atom.
Regions of electron like to be as far away as
possible from the others.
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Regions of electron density
Four regions of electron density around an atom
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Bond Angles in covalent molecules
Linear molecules
2 regions
Trigonal planner molecules
3 regions
Tetrahedral molecules
4 regions
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Unshared electron paires
CH4
NH3
H2O
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Polarity

• It has polar bonds.
• Centers of d and d- lie at different places
  (sides).

H
d

d-
d-
d
d
d
H C H
O C O

d-
H
d
nonpolar molecule
d-
O
d-

N
C
H
H
H
H
d
d
H
polar molecule