Question

Which of the following configurations of an element belongs to the 15${}^{th}$ group of the modern periodic table?

• A. $1s^{2}2s^{2}2p^2$
• B. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^7$
• C. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^3$
• D. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}5p^{6}6s^2$

Answer 1

The correct option is C $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^3$

The general electronic configuration of group 15 elements of the modern periodic table is $n{s}^{2}n{p}^3$.

a) $1s^{2}2s^{2}2p^2$ is the electronic configuration of carbon which belongs to group 14.

b) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^7$ is the electronic configuration of cobalt which belongs to group 9.

c) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^3$ is the electronic configuration of arsenic. So, it has $n{s}^{2}n{p}^3$ electronic configuration and it belongs to group 15 of the periodic table.

d) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}5p^{6}6s^2$ is the electronic configuration of barium and it belongs to group 2 i.e. alkaline earth metal.