Using the perodic table, perdict the formulas of compounds which might be formed by the following pairs of elements : (a) silicon and bromine (b) aluminium and sulphur.

Explanation

(a) Silicon is an element of the `14^(th)` group with a valence 4. Bromine belongs to the `17^(th)` group (halogen family) with valence 1. Hence, the formula of the compound formed would be `SiBr_(4)`.
(b) Aluminium belongs to the `13^(th)` group with a valence 3. Sulphur belongs to the `16^(th)` group (chalcogen family) with valence 2. Hence, the formula of the compounds formed would be `Al_(2)S_(3)`.