Question

Which of the following is not s-block element?

• A. $\left[Ar\right]4s^{2}3d^{10}4p^{6}5s^1$
• B. $1s^{2}2s^{2}2p^1$
• C. $1s^{2}2s^{1}2p^1$
• D. $\left[Ar\right]4s^{1}4p^1$

Answer 1

Answer: (B)

$1s^{2}2s^{2}2p^1$

s-block elements are the elements in which last electron in the electronic configuration (ground state) comes in s-sublevel

(a)$\left[Ar\right]4s^{2}3d^{10}4p^{6}5s^1$ (s-block)

(b) $1s^{2}2s^{2}2p^1$ (p-block)

(c) $1^{2}2s^2$ in ground state - (s-block) and $1s^{2}2s^{1}2p^1$ in excited state.

(d) $\left[Ar\right]4s^2$ - ground state - (s-block) and $\left[Ar\right]4s^{1}4p^1$ - excited state.

Hence $\left(B\right)$ is the correct option.