Molecules and Ions

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Slide 13

Predicting Ionic Charges

Groups 3 - 12: Many transition metals have more than one possible oxidation state.

Iron(II) = Fe2+

Iron(III) = Fe3+

Slide 14

Predicting Ionic Charges

Groups 3 - 12: Some transition metals

have only one possible oxidation state.

Zinc = Zn2+

Silver = Ag+

Slide 15

Writing Ionic Compound Formulas

Example: Barium nitrate

1. Write the formulas for the cation and anion, including CHARGES!

Ba2+

NO3-

2. Check to see if charges are balanced.

3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced

( )

2

Slide 16

Writing Ionic Compound Formulas

Example: Ammonium sulfate

1. Write the formulas for the cation and anion, including CHARGES!

NH4+

SO42-

2. Check to see if charges are balanced.

3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced

( )

2

Slide 17

Writing Ionic Compound Formulas

Example: Iron(III) chloride

1. Write the formulas for the cation and anion, including CHARGES!

Fe3+

Cl-

2. Check to see if charges are balanced.

3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced

3

Slide 18

Writing Ionic Compound Formulas

Example: Aluminum sulfide

1. Write the formulas for the cation and anion, including CHARGES!

Al3+

S2-

2. Check to see if charges are balanced.

3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced

2

3

Slide 19

Writing Ionic Compound Formulas

Example: Magnesium carbonate

1. Write the formulas for the cation and anion, including CHARGES!

Mg2+

CO32-

2. Check to see if charges are balanced.

They are balanced

Slide 20

Writing Ionic Compound Formulas

Example: Zinc hydroxide

1. Write the formulas for the cation and anion, including CHARGES!

Zn2+

OH-

2. Check to see if charges are balanced.

3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.