Question

Based on the group valency of elements state the formula for the following giving justification for each i)Oxides of 1st group elements ii)Halides of elements of group 13 iii)Compounds formed when an element of group 2 combines with an element of group 16.

Answer 1

1)X2O
2)XY where Y are halogens
3)XY

Answer 2

i) oxygen valency is 2

The formula for group 1 oxides is M2O, here M is the group 1 element and O is the oxygen.

ii) group 13 elements valency 3

Valency of halogen : 1

Formula of the halides of the group 13 is MX3, here M is the group 13 elements and X is halogen.

iii) Group 2 elements valency is 2 and group 16 element valency is 2

Formula of the compound is MN where M is the group 2 element and N is the group 16 element.