IONIC COMPOUNDS

REVIEW OF ATOMIC STRUCTURE The structure of the atom

Neutrons + Protons are in the nucleusElectrons in orbits around the nucleus

Neutrons = Zero Charge

Protons = Positive ChargeElectrons = Negative Charge

Atoms in groups 1 – 13 (metals) will lose electrons in order to achieve a full outer shell They become cations (positive)

Atoms in groups 15 – 17 (nonmetals) will gain electrons in order to achieve a full valence shell They become anions (negative)

Combining Capacity: the number of electrons an atom needs to gain or lose to achieve a full outer shell

The positive and negative ions attract to form an ionic bond

IONIC COMPOUNDS – The Octet Rule

IONIC COMPOUNDS – Ionic Charges of the Elements+1

+2 +3 -3 -2 -1

IONIC COMPOUNDS – The Formation of an Ionic Bond

IONIC COMPOUNDS – The Formation of an Ionic Bond Ionic compounds are formed when a metal

(M) is bonded to a nonmetal (N)

In general:

M N MN

M N MN

Rules Assign ionic charges to each atom Apply the criss-cross rule (ONLY the numbers

travel, NOT the sign) Reduce the subscripts by dividing by the highest

common factor Write your chemical formula

IONIC COMPOUNDS – Writing Chemical Formulas

Example 1: sodium and chlorine

IONIC COMPOUNDS – Writing Chemical Formulas

Na Cl+1 -1

Na Cl1 1

ClNa

Example 2: calcium and chlorine

IONIC COMPOUNDS – Writing Chemical Formulas

Ca Cl+2 -1

Ca Cl1 2

ClCa 2

Example 3: lithium and oxygen

IONIC COMPOUNDS – Writing Chemical Formulas

Li O+1 -2

Li O2 1

OLi 2

Example 4: magnesium and oxygen

IONIC COMPOUNDS – Writing Chemical Formulas

Mg O+2 -2

Mg O2 2

OMg

Remember to find the HIGHEST COMMON FACTOR

OMg2 2

Rules…1. Write the metal’s name first2. Write the nonmetal’s name second (change the

ending to “-ide”)

For example: NaCl = sodium chloride

IONIC COMPOUNDS - Naming

IONIC COMPOUNDS - Naming

CaCl2

Li2O

MgO

Calcium chloride

Lithium oxide

Magnesium oxide

Chemical Formula Chemical Name

Some metals can have different combining capacities in different compounds

For example: Copper (Cu) = 1, 2 Iron (Fe) = 2, 3 Lead (Pb) = 2, 4 Tin (Sn) = 2, 4

In these cases, the combining capacity must be specified using Roman Numerals

IONIC COMPOUNDS – Multivalent Metals

These numbers are written as Roman Numerals (i.e. I, II, III, IV, V)

IONIC COMPOUNDS – Multivalent Metals Iron(II) chloride Iron(III) chloride

Iron has two combining

capacities. Iron can have a +2 or

+3 charge.

-1

Fe Cl1 2

ClFe 2

Fe Cl+2 -1

Fe Cl1 3

Fe Cl+3

ClFe 3

“IONIC COMPOUNDS” Worksheet

HOMEWORK