elements that have complete valence electron shells are mostly found in the
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.