CHEMICAL BONDING
THEY CALL IT BONDING…CHEMICAL BONDING
Bonding Atoms
 Why do atoms bond?
- each atom wants a full outermost energy level
- gain, lose, and share valence electrons to achieve
the duet or octet rule aka: “being happy”
- gives each atom an electron configuration similar
to that of a noble gas
ex. Group 18: He, Ne, Ar
Chemical Structure/Models
 Chemical Structure/Molecular Models
- arrangement of bonded atoms or ions
- bond length: the average distance between the
nuclei of two bonded atoms
- bond angles: the angle formed by two bonds
to the same atom
Molecular Models of
Compounds
 Ball and stick
- atoms are represented by balls
- bonds are represented by sticks
* good for “seeing” angles
 Structural
- chemical symbols represents atoms
- lines are used to represent bonds
* good for “seeing” angles
H
H
O
Molecular Models Cont.
 Space filling
- colored circles represent atoms, and the space they take up
- no bonds, no bond angles
 Electron Dot/Lewis Structure
- chemical symbol represent atom
- dots represent valence electrons
- 2 center dots represent a bond
- no bond angles, no bond length
Chemical Bonds
 Chemical Bonds
- attractive force that holds atoms or ions together
- 3 types
ionic, covalent, metallic
- determines the structure of compound
- structure affects properties
- melting/boiling pts, conductivity etc.
Predicting Bond Type
 Definition
Ionic Bonds / Ionic
Compounds
- bond formed by the attraction between oppositely charged
ions
cation: positive: lost e-’s
anion: negative: gained e-’s
- oppositely charged ions attract each other and form an ionic
bond
ex. Na+ + Cl- = NaCl
- electrons are transferred from one atom to another
- negative ions attract more positive ions, and soon a network is
Properties of Ionic
Compounds
 Structure affects properties
- strong attractions between ions: strong bonds
- high melting/boiling pt
- shatter when struck (think of it as one unit)
- conductivity
solid: ions are so close together, fixed
positions, (can’t move)
NO conductivity
liquid: ions are freely moving due to a
broken lattice structure
Good conductivity
 Definition
Covalent Bonds
- chemical bond in which two atoms share a pair of valence
electrons
- can be a single, double, or triple bond
single, 2e-’s (-); double, 4e-’s (=); triple, 6e-’s( )
- always formed between nonmetals
- mostly low melting/boiling points
 2 types of bonds
- polar
- non polar
Covalent Bond Cont.

Non Polar
- bonded atoms that share e-’s equally
- same atoms bonded
ex. Cl – Cl: Cl2

Polar
- bonded atoms that do not share e-’s equally
- different atoms bonded
H
ex. H – N – H: NH3
Metallic Bonds
 Definition
- a bond formed by the attraction between positively charged
metal ion (cation) and the shared electrons that surround it
(sea of electrons)
ex. Cu
 Properties
- Conductivity: Good: electrons can move freely
- Malleable: lattice structure is flexible
 Monoatomic Ions
Naming Ions
- cation
-name of element with ion
ex. (Na) Sodium (Na+) Sodium ion
- anion
- name of element with the suffix –ide
ex. (Br) Bromine (Br-) Bromide
 Ions with multiple cations
- transition metals
- most form 2+, 3+ and 4+
ex. Cu+, Cu2+
Naming Metals with
Multiple Ions
 Transition Metals
- form multiple ions
- in order to name the ion use a roman numeral to
indicate the charge
ex. Cu2+: Copper (II), Titanium (III): Ti3+
Practice Problems:
Fe3+: Iron (III)
Mercury (III): Hg3+
Pb4+: Lead (IV)
Chromium (II): Cr2+
Polyatomic Ions
 Definition
- an ion made of one or more atoms that are covalently bonded
and that act as a unit
(atoms that have lost or gained electrons)
ex. CO3 2- , NH4+
- behave the same as other ions
- polyatomic ions can combined like
any other ion (as a unit)
ex. NH4NO3
(NH4)2SO4
1:1 ratio
2:1 ratio
Polyatomic Ions

Naming polyatomic ions
- not logical
- rules for some compounds

-ite & -ate endings
- indicates the presence of oxygen
- called oxyanions
- if (-) does not specify how many oxygen atoms
present
ex. Sulfate:4, Nitrate:3, Acetate:2
are
Polyatomic Ions Cont.
- often several oxyanions differ only in the number
of oxygen atoms present
ex. Sulfur
- ion with more oxygen takes the –ate
ex. SO4
- ion with less takes the –ite ending
ex. SO3
 Common Oxyanions
* Make sure you know these: memorize
ending
Polyatomic Ions Cont.
 Common Polyatomic Ions
Naming Ionic Compounds
 Naming ionic compounds (binary)
Formula to Name
- name of cation followed by the name of the anion
ex. NaCl: Sodium Chloride
ZnO: Zinc (II) Oxide
CuCl2: Copper (II) Chloride
- formulas must indicate the relative number of cations and
ions if transitional
Naming Ionic Compounds

Practice Problems
MgBr2
Magnesium Bromide
KI
Potassium Iodide
CuCl2
Copper (II) Chloride
Fe2S3
Iron (III) Sulfide
Formulas of Ionic
Compounds
 Writing formulas for ionic compounds
Name to Formula
- balance the cation charge and anion charge, leaving NO net charge
- use subscripts to denote the number of atoms in the formula
ex. NaCl: Na+ Cl- : NaCl
CaCl: Ca2+ Cl- : CaCl2
**1 to 1 ratios do not designate charge**
**Criss-Cross charges into subscripts**
Practice Problems
 Write the formula for the following atoms
a.
lithium oxide
Li2O
b.
beryllium chloride
BeCl2
c.
titanium (III) nitride
TiN
d.
cobalt (III) hydroxide
Co(OH)3
Naming
Covalent
Compounds
 Prefix System
# of atoms
prefix
1
mono
2
di
3
tri
4
tetra
5
penta
6
hexa
7
hepta
8
octa
9
nona
10
deca
Naming Covalent Compounds
Cont.
 Rules for the prefix system
1. less electronegative element is given first. It is given a prefix
only if it contributes more than one atom to a molecule of the
compound
2. The second element is named by combining (a) a prefix
indicating the number of atoms contributed by the atom (b) the
root of the name of the second element, and (c) the ending –ide
3. The o or a at the end of a prefix is usually dropped when the
word following the prefix begins with another vowel
ex. Monoxide or pentoxide
Naming Covalent Compounds
Cont.
Naming covalent compounds from formula
1. SiO2
Silicon dioxide
2. PBr3
Phosphorus tribromide
3. CI4
Carbon tetraiodide
4. N2O3
Dinitrogen trioxide
Writing Formulas for
Covalent Compunds

Writing formulas from names
1.
Carbon Dioxide
CO2
2.
Dinitrogen Pentoxide
N2O5
3.
Triphosphorus monosulfide
P3 S
4.
Sulfur Monobromide
SBr