How many valence electrons does a phosphorus (P) atom have?

• A. 7
• B. 5
• C. 6
• D. 3

Answer: (B)

Verified step by step guidance

1. Identify the element in question, which is phosphorus (P).
2. Determine the atomic number of phosphorus, which is 15, meaning it has 15 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 phosphorus: \$1s^2 2s^2 2p^6 3s^2 3p^3$.
5. Count the electrons in the outermost shell (the third shell): \$3s^2\( and \)3p^3\( add up to \)2 + 3 = 5$ valence electrons.