Question

Using the periodic table predict the formula of the compound formed by the following pairs of elements.
a) Mg and S
b) Si and Br​

Answer 1

a) Mg : valency=2

S :valency=2

compound : MgS

b) Si: valency=4

Br :valency=1

compound : SiBr4

Answer 2

a) Mg and S:

The element name of the symbol ‘Mg’ is magnesium.

The element name of the symbol ‘S’ is sulphur.

The compound formed is magnesium sulphide $\text{MgS}$ which is brown in colour and is in powder state. It is used to remove sulphur during basic oxygen steel making process.

b) Si and Br:

The element name of the symbol ‘Si’ is silicon.

The element name of the symbol ‘Br’ is bromine.

The compound formed is silicon tetrabromide $\text{SiBr}_4$ which is a colourless liquid which suffocating odor. It is used in ceramics and sealants.