Question

Which of the following corresponds to the configuration?
$1s^{2}2s^{2}2p^{6}3s^{2}3p^6$

• A. He
• B. Na
• C. Mg
• D. Ar

Answer 1

Answer: (D)

Ar

Atomic number = no. of $e^{-}s$ = 18

$\therefore$ Argon $=1s^{2}2s^{2}2p^{6}3s^{2}3p^6$

Option D is correct.