Question

Three elements A, B and C have 3, 4 and 2 electrons respectively in their outermost shell. Give the group number to which they belong in the Modern Periodic Table. Also, give their valencies.

Answer 1

1. Element A has 3 valance electrons so, its valency is 3 and it belongs to group 13 in the modern periodic table.
2. Element B has 4 valance electrons so, its valency is 4 and it belongs to group 14 in the modern periodic table.
3. Element C has 2 valance electrons so, its valency is 2 and it belongs to group 2 ​in the modern periodic table.