Question

Shade all the elements for which the neutral atom has a valence electron configuration of ns2np6 , where n stands for an integer.

Answer 1

The elements for which the neutral atom has a valence electron configuration of .

$ns^2np^6$

are those whose valence electron shell has 2 + 6 = 8 electrons.

Those are the noble gases, except helium (He).

Here is the list of the noble gases and the configuration of their valence electron configuration:

He:     $1s^2$

Ne      $2s^22p^6$

Ar       $3s^23p^6$

Kr       $4s^24p^6$

Xe       $5s^25p^6$

Rn      $6s^26p^6$

Answer: Ne, Ar, Kr, Xe and Rn