Question

An atom has electronic configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{3}4s^2$. It will be place it in :

• A. fifth group
• B. fifteenth group
• C. second group
• D. third group

Answer 1

The correct option is A fifth group

An atom has an electronic configuration :

$1s^2,2s^{2}2p^6,3s^{2}3p^{6}3d^3,4s^2$

It is a member of $d$-block element because the last electron is filled in $d$-shell as $3d^3$ and the following electronic configuration is possible for $d$-subshell as $(n-1)$ $d$-subshell.

Thus, it is a member of the fifth group.

Hence, the correct option is A.