Name: _____________________________ Date: ___________________ Period: _______

Practice 6.2: Writing Ionic Formulas Part II When writing chemical formulas for ionic compounds keep in mind these rules:

x The metal ion is always written first in the formula. x The metal ion and the non-metal ion charges MUST always add up to zero. x Never write the number “1” as a subscript:  EXAMPLE:  H2O not H2O1

The steps: 1. Write the charges of each ion. Ex: Ca+2 N-3 2. If they automatically add up to zero, smash them together. Ex: Ba+2 O-2 o BaO 3.  If they don’t add up to zero, do a criss-cross on them. (Leave out the “+” and “-” signs). Ex:

Ca+2 N-3

Ca 3 N 2 4. Polyatomic ions are group of ions that act as 1 BIG ion. If you need more than one of these in

the formula, use parenthesis and write the subscript outside. Ex:

Ba+2 CN-1

Ba (CN) 2 Part A: Name/Write the following ions

Name Ion Nitride

O2-

Fluoride

Cl-

Bromine

I-

Sulfide

Fe2+

Lithium

Na+

Magnesium

Ca2+

Name: _____________________________ Date: ___________________ Period: _______ Part B: Write the formulas for the following compounds Ions Formula Calcium with chloride Ca2+ Cl- CaCl2

Barium with oxygen

Lithium with nitrogen

Aluminum with fluorine

Calcium with oxygen

Cesium with nitrogen

Aluminum with oxygen

Potassium with sulfur

Magnesium with bromine

Sodium with iodide

Part C: Write the formulas for the following polyatomic compounds Ions Formula Aluminum with hydroxide Al3+ OH- Al(OH)3

Sodium with carbonate

Calcium with phosphate

Barium with acetate

Potassium with chromate

Rubidium with cyanide

Magnesium sulfate

Aluminum phosphate

Sodium bicarbonate

Unit 6.3

1. Do criss-cross to get formula.

2. Draw each outer orbital diagram for each atom.

3. Use an arrow to show the transfer from the metal to the nonmetal.

� Ex. �Mg +2 Cl -1 so....MgCl2� Mg ÇÈ� Cl ÇÈ ÇÈ ÇÈ Ç� Cl ÇÈ ÇÈ ÇÈ Ç

� Use an orbital diagram to show the transfer of e-- between potassium and oxygen.

� K +1 O -2 so....K2O

� Use an orbital diagram to show the transfer of e-- between aluminum and sulfur� Al2S3

� Cation is named first� Group 1 and 2 and Al are “as is”� transition elements – element name followed by (roman numeral) for

the charge� Ex. Fe2O3

� Iron (III) Oxide

� Anion is named second� Monatomic - add “ide” to the stem of the word� Polyatomics – see cheat sheet

� Remember…� Cu can be +1 or +2. Fe can be +2 or +3. So....� Copper (II) means copper with a +2 charge.� Iron (III) means iron with a +3 charge.

� EXAMPLE:

� O -2 = oxide

� S -2 = sulfide

� Br-1 =

� I -1 =

� Name: CuO

� Answer:

� Name: Al2O3

� Answer:

� Name: Ca(OH)2

� Answer:

� Name: FeCl3� Answer:

� Name: Cu(NO3)2

� Answer: