How many valence electrons does the element boron (B) have?

• A. 2
• B. 5
• C. 3
• D. 4

Answer: (C)

Verified step by step guidance

1. Identify the atomic number of boron (B), which is 5. This means boron has 5 electrons in total.
2. Recall that valence electrons are the electrons in the outermost shell (energy level) of an atom.
3. Determine the electron configuration of boron: \$1s^2 2s^2 2p^1$.
4. Recognize that the first shell (1s) is full and not part of the valence shell; the valence shell is the second shell containing \$2s^2 2p^1$ electrons.
5. Count the electrons in the outermost shell: \$2 + 1 = 3$ valence electrons for boron.