Question

1. which species does not have a noble gas electron configuration? s ar mg2+ na+

Explanation:

Step1: Recall noble - gas electron configurations

Noble - gas electron configurations are stable electron arrangements where the outermost shell is fully filled.

Step2: Analyze each species

• Sulfur (S): Sulfur has 16 electrons. Its electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{4}\), which is not a noble - gas configuration.
• Argon (Ar): Argon is a noble gas with 18 electrons and electron configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}\), a noble - gas configuration.
• Magnesium ion (\(Mg^{2 +}\)): Magnesium has 12 electrons. \(Mg^{2+}\) has lost 2 electrons, so it has 10 electrons with electron configuration \(1s^{2}2s^{2}2p^{6}\), which is the same as neon (a noble gas), a noble - gas configuration.
• Sodium ion (\(Na^{+}\)): Sodium has 11 electrons. \(Na^{+}\) has lost 1 electron, so it has 10 electrons with electron configuration \(1s^{2}2s^{2}2p^{6}\), which is the same as neon (a noble gas), a noble - gas configuration.

Answer:

S