Question

Elements that have complete valence electron shells are mostly found in the

Answer 1

Noble gases have complete valence electron shells

Answer 2

Explanation:

Elements of group 18 are known as noble gases. The elements of this group are He, Ne, Ar, Kr, Xe, and Rn.

The electronic configuration of He is $1s^{2}$.

The electronic configuration of Ne is $1s^{2}2s^{2}2p^{6}$.

The electronic configuration of Ar is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}$.

The electronic configuration of Kr is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}$.

The electronic configuration of Xe is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}5p^{6}$

The electronic configuration of Rn is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}5p^{6}4f^{14}5d^{10}6s^{2}6p^{6}$.

Thus, we can conclude that elements of group 18 have  complete valence electron shells.