Question

The atomic number of three elements A, B and C are 17,10and 11....which one of them will form an anion and why?

Answer 1

Electronic configurations are as follows :

Element A:

17-- 2,8,7

It will gain 1 electron so it will form Anion

Element B:

10--2,8

It is a noble gas since last shell is completely filled

Element C

11-- 2,8,1

It will loose 1 electron to be noble so it will form Cation

Hence, A will form Anion

Hope this helps !!