## Naming Ionic Compounds

• Ions can join together to form compounds.
• They join in such a way that their charges cancel out and the resulting compound is neutral (we will practise this later).
• To name an ionic compound:
1. Identify the two ions that make up the compound
2. Write the name of each ion in that same order
3. Hint: The positive ion (metal) will always come first
4. Hint 2: It is important to include the (II) or (III) if it is part of the ion name.

### Whakawai

1. $CaCO_{3}$
• $Ca^{2+}$ and $CO_{3}^{2-}$ ions $\rightarrow$ Calcium Carbonate
2. $MgSO_{4}$
• Magnesium Sulfate
3. $Fe(OH)_{2}$
• Iron (II) Hydroxide
4. $Fe(OH)_{3}$
• Iron (III) Hydroxide

### More Whakawai

• Collect a sheet from the front.
• This sheet includes every variation of ionic compounds that you should see this year!
• Answer 20 today, but you should be able to do all of them before we have a test.

## Forming Ionic Compounds

### When Ions Have Equal Charges

• Some ionic formulae are easy to generate
• This occurs when they have equal and opposite charges. E.g.
• Potassium Chloride: $K^{+}$ and $Cl^{-1}$.
• Simply remove the charges and join them together: $KCl$.
• Magnesium Sulfate: $Mg^{2+} + SO_{4}^{2-} \rightarrow MgSO_{4}$
• Notice how the charge is removed, but we keep it $O_{4}$! That is because the 4 tells us how many oxygen atoms there is!

### Whakawai / Practise

Make these simple ionic compounds:

1. Hydrogen Chloride
2. Calcium Sulfide
3. Aluminium Phosphate
4. Ammonium Hydrogen Carbonate
5. Potassium Hydroxide
6. Iron (II) Oxide
7. Zinc Sulphate
8. Iron (III) Nitride

## Akoranga 13 Mahi Tuatahi

Form these simple ionic compounds:

1. Copper Sulfate
2. Sodium Nitrate
3. Potassium Chloride
4. Aluminium Nitride
5. Iron (III) Phosphate

## Te Whāinga Ako

1. Be able to form complicated ions using swap-and-drop

Write the date and te whāinga ako in your book

### When the Charges are Unequal

Swap and Drop!

1. Remove the sign from the charges (+/-)
2. Swap the numbers between the ions
3. Drop them down to the bottom
Lithium OxideAluminium HydroxideAmmonium Sulphate
Charges
Swap
Drop
Compound

#### Whakawai / Practise

Make these more complicated ionic compounds:

1. Hydrogen Sulphate
2. Lithium Oxide
3. Calcium Carbonate