Which of the following pair of atomic numbers represents s-block element?

Options

A. 7, 15
B. 6,12
C. 9,17
D. 3,20

Answer

D

Explanation

`Z= 3: 1s^(2) 2s^(1), Z= 20: [Ar] 4s^(2)`
In both elements valence electrons enter s-subshell thus both are s-block elements.