How many unpaired electrons are present in the ground-state electron configuration of a carbon atom?

• A. 0
• B. 4
• C. 2
• D. 1

Answer: (C)

Verified step by step guidance

1. Identify the atomic number of carbon, which is 6. This means a neutral carbon atom has 6 electrons.
2. Write the ground-state electron configuration of carbon by filling orbitals in order of increasing energy: 1s, 2s, then 2p. The configuration is \$1\mathrm{s}^2 2\mathrm{s}^2 2\mathrm{p}^2$.
3. Focus on the 2p subshell, which has three orbitals and can hold up to 6 electrons. Since carbon has 2 electrons in the 2p subshell, these electrons will occupy separate orbitals to minimize electron repulsion according to Hund's rule.
4. Apply Hund's rule: place one electron in each of two different 2p orbitals with parallel spins, resulting in unpaired electrons.
5. Count the number of unpaired electrons in the 2p subshell, which corresponds to the number of orbitals occupied by a single electron. This gives the total number of unpaired electrons in the ground state of carbon.