Question

A) how does the tendency to gain electrons change as we go down to a group? reason

Answer 1

On moving down a group ,the tendency to gain electrons decreases as the atomic radius increases due to the increase in the number of shells .This increases the distance between the nucleus and the outer most shell...Hence it is easy to lose electrons instead of gaining electrons
.
.
.
Hope you like this answer...
.
.
.
.

Answer 2

Tendency to gain electrons decreases on moving down the group because with increase in size, effective+ve nuclear charge decreases.