State whether the following statements are true or false:

(a) A sodium ion has positive charge because it has more protons than a neutral atom

(b) A chloride ion has negative charge because it has more electrons than a neutral atom

Define ‘formula mass’ of a compound.

What do we call those particles which are formed:

(a) by the gain of electrons by atoms?

(b) by the loss of electrons by atoms?

Write down the formulae for the following compounds:

(a) Calcium oxide

(b) Magnesium hydroxide

An element Z has a valency of 3. What is the formula of oxide of Z?