Question

1 multiple answer 1 point which electron configurations below are stable? (multiple answer may apply; select all correct answers) 1s² 2s² 2p⁶ 1s² 2s² 2p³ 1s² 2s² 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵

Explanation:

Stable electron configurations often follow the octet rule (except for some elements with fewer electrons) and fill sub - shells completely. Noble gas electron configurations are stable.

1. $1s^{2}2s^{2}2p^{6}$ is the configuration of neon, a noble gas, so it is stable.
2. $1s^{2}2s^{2}2p^{3}$ is the configuration of nitrogen, not a noble - gas configuration but is a stable configuration for nitrogen as it has a half - filled p - subshell which gives it some stability.
3. $1s^{2}2s^{2}$ is the configuration of beryllium, a stable configuration for beryllium as it has filled its 1s and 2s subshells.
4. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}$ is the configuration of krypton, a noble gas, so it is stable.
5. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}$ is the configuration of zinc, a stable configuration as it has filled its d - subshell.
6. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{5}$ is the configuration of bromine, not a noble - gas configuration and is not as stable as the above ones in terms of having a complete outer shell.

Answer:

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