unlike covalent bonds, ionic bonds are attraction between ...unlike covalent bonds, ionic bonds are...

Unlike covalent bonds, ionic bonds are not “ACTUAL BONDS,” but forces of attraction between oppositely charged ions.

They stay together in a CRYSTAL LATTICE.

There are 3 Types of ionic compounds:

A. Binary Ionic Compoundsi. Simple

ii. Multivalent

B. Polyatomic Ionic Compounds

C. Hydrated Ionic Compounds

“Binary” means only 2 types of ions involved

i. Simple binary compounds involve a metal ion (+) and a nonmetal ion(-).

How to write the name, given the formula:

RULES:

1. Write the name of the CATION before the ANION (Be positive before being negative )

2. Change the ending of the ANION name to “-ide”

3. Do not use PREFIXES!

Examples:

◦ MgBr2 _________________________________◦ KCl _________________________________◦ Na2S _________________________________◦ Mg3P2 _________________________________◦ Ba3N2 _________________________________

What’s wrong with the following names for BaS?

◦ barium sulfur ____________________________◦ Barium Sulfide ____________________________◦ barium sulfuride ____________________________

How to write a formula, given the name:

RULES:

1. Write element symbols.

2. Look up the ION CHARGE on the periodic table.

3. Use the “crossover” method to determine the numbers of each ion in the compound.

4. Ion ratios are always in the lowest common multiple (reduce).

Examples:

a) sodium bromide _____________________

a) barium iodide ___________________

c) magnesium oxide _____________________

d) aluminum oxide ___________________

ii. Multivalent

Ions of some transition elements can have more than one possible charge.

Example: Copper (Cu) can have a charge of 2+ and 1+

ROMAN NUMERALS are used to indicate the which charge

1+ I2+ II3+ III4+ IV5+ V6+ VI

If the charge is not specified, use the top charge.

How to write the formula, given the name:

RULES:

1. Use ROMAN NUMERALS to determine the ION CHARGE of the MULTIVALENT ION.

2. If ROMAN NUMERAL are NOT given, use the charge found on the top in each box on the table.

Examples:

a) copper (II) oxide _________________________

b) lead (IV) sulfide _________________________

a) tin sulfide _________________________

How to write the name given the formula:

RULES:

1. Write the names of the ions.

2. Write the Roman Numeral for the multivalent ion by reversing the cris-cross to see what was the original charge. If it is different, iconic charges must have been reduced.

Examples:

a) PbI2 _________________________

b) Fe2O3 _________________________

c) CuCl _________________________

d) MnO2 _________________________

◦ Polyatomic ions are GROUPS OF ATOMS acting as 1 ION, carrying an OVERALL CHARGE.

On the back of your periodic table, there is a POLYATOMIC ION TABLE.

Endings of polyatomic ions are easily recognizable as they are often –ATE or –ITE, providing a good clue.

Examples:

◦ nitrate ________◦ nitrite ________◦ cyanide ________◦ hydroxide ________◦ bicarbonate ________ (aka: hydrogen carbonate)

◦ chlorate ________◦ carbonate ________◦ sulfate ________◦ phosphate ________◦ ammonium ________◦ acetate ________◦ bisulfate ________ (aka: hydrogen sulfate)

How to write the name given the formula:

RULE:

Write out the name of each element and polyatomic compound.

Examples:

a) NaHSO4 _____________________

b) Mg(NO3)2 _____________________

c) HNO3 _____________________

d) NaOH _____________________

e) KMnO4 _____________________

f) Cu2SO4 _____________________

How to write the formula given the name:

RULES:

1. Write element and polyatomic symbols.

2. Look up the ION CHARGE on the periodic table.

3. Use the “crossover” method to determine the numbers of each ion in the compound.

4. Ion ratios are always in the lowest common multiple (reduce).

Examples:

a) lithium sulfate _____________________

b) ammonium carbonate _____________________

c) hydrogen dichromate _____________________

d) sodium acetate _____________________

Hydrated ionic compounds have WATERattached to their crystal lattice structure.

Examples: ◦ Bluestone CuSO4 ∙5H2O

◦ 5 H2O molecules attached to each CuSO4 compound.

◦ The “dot” represents a weak bond.

We indicate the number of water molecules with our GREEK PREFIXES:

Number Prefix

1 mono

2 di

3 tri

4 tetra

5 penta

6 hexa

7 hepta

8 octa

9 nona

10 deca

How to write a formula given a name:

Examples:

a) barium chloride dihydrate

b) potassium hydroxide hexahydrate

c) sodium carbonate octahydrate

d) cobalt (II) chloride decahydrate

How to write a name given a formula:

a) CaSO4 ∙2H2O

b) Na3PO4 ∙4H2O

c) HCN ∙ 3H2O