Ch 5 & 6: Bonding, Formulas
and Naming Notes
Types of Chemical Bonds:
A. Ionic Bonding
1) Positively charged ions are attracted to negatively
charged ions, making a neutral compound.
2) Properties of Ionic Compounds:
a) high melting points.
b) dissolve in water to form solutions that are
good conductors of electricity (electrolytes).
c) have a large electronegativity difference
between elements.
d) usually form between metals and nonmetals.
3) The Octet Rule:
a) Atoms tend to gain or lose electrons in order to
acquire a full set of valence electrons (stable octet).
b) Atoms will transfer electrons (e-) to each other in
order to have a full set of valence electrons.
c) When electrons are transferred, ionic bonds are
formed.
Ions
• Atoms can form ions by gaining or losing
electrons.
– Metals tend to lose one or more electrons to form
positive ions called cations.
– Cations are generally named by using the name of
the parent atom.
Ions
• Nonmetals tend to gain one or more electrons
to form negative ions called anions.
• Anions are named by using the root of the
atom name followed by the suffix –ide.
4) Types of Compounds:
a) Binary form from monatomic ions – have 1
cation and 1 anion.
Ex) Mg+2 O-2 MgO
Ca+2 Cl-1 CaCl2
+1
-2
Not Balanced
Na +1 Na +1
O -2
2 x +1 = +2
1 x -2 = -2
2 + (- 2) = 0
Balanced
Na2O
+3
-2
Not Balanced
Al +3
Al +3
O -2
O -2
3 x -2 = -6
2 x +3 = +6
+ 6 + (- 6) = 0
O -2
Balanced
Al2O3
4) Types of Compounds:
b) Tertiary form from polyatomic ions which
consists of a group of atoms covalently
bonded with a single charge that bond
ionically with other ions.
NH4+1
SO4-2
Ex.
“ammonium sulfate” ,
(NH4)2SO4
Name this compound:
FeO
X
Iron oxide
Fe+2 O-2
Iron (II) oxide
If that’s correct, name this:
Fe+3 O-2
Fe2O3
Iron (III) oxide
How can we distinguish between these compounds?
What is the charge on the oxygen in each compound?
Then what is the charge on the iron in each compound?
Fix the name of the first compound:
Ions
Ion Charges and the Periodic Table
5) Polyvalent Metals:
Some metals including the transition metals do not
follow the octet rule and may form more than 1
kind of cation. These ions are named with roman
numerals to distinguish between them.
Ex) Fe+2 iron (II) read “iron two”
Fe+3 iron (III) read “iron three”
FeCl2 iron (II) chloride
FeCl3 iron (III) chloride
Copper (I) sulfate Cu2SO4
Copper (II) phosphate Cu3(PO4)2
6) Lewis Dot Diagrams for elements:
Element
# of val. Electrons Dot Diagram
Li
1
N
5
Be
2
F
7
Ne
8
Au
2
**Note: Only show s and p orbitals in dot diagram.
Li
Electron Dot Diagram for Atoms and Ions
7) Lewis-dot diagram for sodium chloride:
[Na+] [
-]
B. Covalent Bonding
1) Covalent Bonds are formed by sharing pairs of
electrons between 2 atoms.
2) Usually formed between two nonmetals with a
low electronegativity difference.
3) Molecules:
a) a group of atoms held together by covalent
bonds
b) molecular substance – contains molecules
4) Naming:
a) uses prefixes: 1 mono- 4 tetra2 di3 tri-
5 penta6 hexa-
7 hepta8 octa9 nona-
10 deca-
b) end in “ide”
c) More electronegative element is written last
d) Only use a prefix on the first element if it is more
than one.
e) Always use a prefix for the second element.
Ex) water H2O dihydrogen monoxide
smog NO2 nitrogen dioxide
5) Types of formulas for covalent bonding
a) Molecular Formula shows how many atoms
make up a compound.
ex. CH4 & H2O
b) Structural Formula shows how the atoms are
bonded to each other.
ex.
1. Uses 2 dots to show an unshared pair of
electrons.
2. Uses dashes to represent covalent bonds (a
shared pair of electrons) in a structural
formula.
3. The octet rule should be satisfied for each
element in the compound.
c) Empirical Formula is the lowest whole number
ratio of all the elements in the compound.
Ex) C6H6
=
CH
C6H12O6 =
CH2O
6) Multiple Bonds – can be used to satisfy
the octet rule
Single Bonds – Share 1 pair of electrons.
Ex) methane or phosphorous trichloride
Double Bonds – Share 2 pairs of electrons.
Ex) formaldehyde
Triple Bonds – Share 3 pairs of electrons (strongest
bond).
Ex) ethyne
8) Properties of Covalent Bonds
a) Low melting points, brittle, strong odor, poor
conductors of electricity.
b) Polar Bonds – form between elements with large
differences in electronegativity. These have an
uneven sharing of electrons.
Ex) water
c) Nonpolar bonds – exert equal pull on the
electrons.
Ex) O2
9) Electronegativity Chart is used to determine
bond type
non polar covalent
0
0.4
polar covalent
ionic bonds
1.9
even sharing uneven sharing
- no charge
– slight charge
on molecule
4.0
electrons transferred
– forms ions
C. Ionic & Covalent Bonds Summary:
Ionic Bonding
Covalent Bonding
metal-nonmetal
nonmetal-nonmetal
e- transferred
e- shared
large electronegativity difference
(>1.9)
electronegativity difference (0 1.9)
ions formed
no ions
written cation (+) anion (-)
more electronegative element written
last
name cation - name anion
use # prefixes/ends in ide
forms ionic compound (formula unit)
in a crystal lattice
forms molecules
Written with a chemical or empirical
formula
Written with a molecular or
structural formula
NaCl – sodium chloride
CCl4 – carbon tetrachloride
[Na+] [
-]
carbon tetrachloride
D. Acids:
1) A molecular compound that dissolves in
water to produce H ions and a
characteristic anion.
2) In water, acids behave like ionic
compounds.
3) Most acid formulas begin with H.
(Except organic acids) “ COOH”
4) The number of hydrogens in the formula
depends upon the charge of the anion.
5)Types of Acids
a.) Organic Acids contain the carboxylic group,
-COOH or
Ex) CH3COOH acetic acid (vinegar)
(or HC2H3O2)
b.) Binary Acids contain hydrogen and 1 type of anion.
A two-word name is used for binary acids.
1st word: prefix is “hydro”
root is formed from the anion
anion suffix “ide” is changed to “ic”
2nd word: is “acid”
Ex)
HCl
anion is chloride
hydrochloric acid
Prefix
HBr
root
suffix
anion is bromide hydrobromic acid
c.) Oxo (Tertiary) Acids: contain oxygen within a
polyatomic ion.
A two-word name is used for oxo acids.
H2SO4
H2SO3
sulfate
sulfite
sulfuric acid
sulfurous acid
sulfur or phosphor (to sound better)
2nd word is “acid”
If you “ate” something you don’t like, you say “ic”
“ite-ous”
HNO3
anion is nitrate
nitric acid
root
H3PO3 anion is phosphite
suffix
phosphorous acid
Nitrous acid, anion is nitrite formula is: HNO2
Phosphoric acid, anion is phosphate
formula is: H3PO4
E. Hydrates:
1.) Ionic compounds that absorb H2O into their
solid structures.
Ex) magnesium sulfate heptahydrate (epsom salt)
Formula: MgSO4  7H2O
2.) Anhydrous substance – substance without water
MgSO4
Ex) CuSO4 • 5H2O copper (II) sulfate pentahydrate
(bright blue)
CuSO4 – anhydrate (light blue/white)