State the information obtained from the formula of a compound.

Gold is used to make jewellery because it is:

1. dull
2. lustrous and attractive
3. highly reactive
4. very cheap

The hardest naturally occuring substance is:

1. graphite
2. iron
3. diamond
4. coal

The inert gas filled in electric bulbs is:

1. Helium
2. Argon
3. Neon
4. Both (1) and (3)