How many valence electrons does a chlorine atom have?

• A. 7
• B. 5
• C. 6
• D. 8

Answer: (A)

Verified step by step guidance

1. Identify the element in question, which is chlorine (Cl).
2. Determine the atomic number of chlorine, which is 17, meaning it has 17 electrons in total.
3. Recall that valence electrons are the electrons in the outermost shell (energy level) of an atom.
4. Write the electron configuration of chlorine: \$1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{5}$.
5. Count the electrons in the outermost shell (the third shell): \$3s^{2} 3p^{5}$, which sums to 7 valence electrons.