select the correct answer. which element has three unpaired electrons in its p orbital? a. carbon (atomic…

Explanation:

Step1: Write electron - configurations

Use the Aufbau principle to write electron - configurations for each element.

• Carbon (Z = 6): $1s^{2}2s^{2}2p^{2}$. The $2p$ sub - shell has 2 electrons, which are unpaired according to Hund's rule.
• Oxygen (Z = 8): $1s^{2}2s^{2}2p^{4}$. The $2p$ sub - shell has 4 electrons. According to Hund's rule, there are 2 unpaired electrons in the $2p$ sub - shell.
• Nitrogen (Z = 7): $1s^{2}2s^{2}2p^{3}$. The $2p$ sub - shell has 3 electrons. According to Hund's rule, each of the 3 electrons occupies a different $2p$ orbital with parallel spins, so there are 3 unpaired electrons in the $2p$ sub - shell.
• Beryllium (Z = 4): $1s^{2}2s^{2}$. It has no electrons in the $p$ orbital.

Answer:

C. nitrogen (atomic number 7)