Carbon has six protons. How many valence electrons does carbon have?

• A. 6
• B. 8
• C. 2
• D. 4

Answer: (D)

Verified step by step guidance

1. Recall that the number of protons in an atom equals its atomic number, which for carbon is 6.
2. Determine the electron configuration of carbon by filling electrons into atomic orbitals in order of increasing energy: 1s, 2s, then 2p.
3. Write the electron configuration for carbon: \$1s^2 2s^2 2p^2$.
4. Identify the valence electrons as those in the outermost shell, which for carbon is the second shell (2s and 2p orbitals).
5. Count the electrons in the 2s and 2p orbitals: \$2 + 2 = 4$ valence electrons.