Question

A metal has electronic configuration $[Ar{]}^{18}3d^{7}4s^2$. On the basis of this electronic configuration, find out the group number.

• A. 10
• B. 12
• C. 9
• D. 13

Answer 1

The correct option is C 9

Here, the last electron enters in d-subshell, so it belongs to d-block elements.
For d-block elements group number
=no of electrons in (n-1) d subshell+ number of electrons in valence shell(i.e. ns)
so,
group number=7+2=9.