Compound Names (SQA National 5 Chemistry): Revision Note

• When writing the name of the non-metal part of the compound remember that the ending will not be -ide

  • -ide is used when a non-metal becomes an ion

  • For example:

    • Oxygen becomes oxide

    • Nitrogen becomes nitride

    • Sulfur becomes sulfide

    • Bromine becomes bromide

• Some compounds ending in –ide contain three elements

  • These are metal hydroxides, which include oxygen and hydrogen as part of the hydroxide ion (OH⁻)

• For example:

  • Sodium hydroxide (NaOH) contains:

    1. Sodium (Na)

    2. Oxygen (O)

    3. Hydrogen (H)

For ions containing the same elements, –ate means there are more oxygen atoms than –ite

For example:

• Sulfate = SO₄^2-

• Sulfite = SO₃^2-

• Nitrate = NO₃^-

• Nitrite = NO₂^-

Identify the elements in the following compounds:

1. Lithium oxide

2. Zinc iodide

3. Silver hydroxide

4. Potassium nitrate

5. Iron (III) carbonate

6. Calcium phosphate

[6]

Answers:

1. Lithium bromide

   • The -ide ending indicates only 2 elements are involved

   • The elements are lithium and oxygen [1 mark]

2. Zinc iodide

   • The -ide ending indicates only 2 elements are involved

   • The elements are zinc and iodine [1 mark]

3. Silver hydroxide

   • The -ide ending normally indicates 2 elements are involved

   • But, the hydroxide name indicates hydrogen and oxygen

   • The elements are silver, hydrogen and oxygen [1 mark]

4. Potassium nitrate

   • The -ate ending indicates 3 elements are involved including oxygen

   • Nitrate indicates nitrogen and oxygen

   • The elements are potassium, nitrogen and oxygen [1 mark]

5. Iron (III) carbonate

   • The -ate ending indicates 3 elements are involved including oxygen

   • Carbonate indicates carbon and oxygen

   • The elements are iron, carbon and oxygen [1 mark]

6. Calcium phosphate

   1. The -ate ending indicates 3 elements are involved including oxygen

   2. Phosphate indicates phosphorus and oxygen

   3. The elements are calcium, phosphorus and oxygen [1 mark]