| 1. | ELEMENTS | COMPOUNDS |
| hydrogen | nitrogen dioxide | |
| lead | sodium chloride | |
| iron | carbon dioxide | |
| magnesium | water |
| 3. | |
| a) | aluminium & sulfur |
| b) | magnesium, nitrogen and oxygen |
| c) | hydrogen, chlorine |
| d) | lithium, sulfur & oxygen |
| e) | calcium, hydrogen & oxygen |
| f) | silicon & oxygen |
