Question

Which of the following configurations represents a noble gas?

• A. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}$
• B. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4f^{14}5s^{2}$
• C. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}5p^{6}$
• D. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}5p^{3}$

Answer 1

Answer: (C)

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}5p^{6}$

Answer 2

: The outermost shell configuration of the element shows 8 electrons hence it is a noble gas.