How many valence electrons are present in a neutral atom of aluminum (Al)?

• A. 2
• B. 5
• C. 1
• D. 3

Answer: (D)

Verified step by step guidance

1. Identify the atomic number of aluminum (Al), which is 13. This means a neutral aluminum atom has 13 electrons.
2. Write the electron configuration of aluminum to determine the distribution of electrons in its shells: \$1s^2 2s^2 2p^6 3s^2 3p^1$.
3. Recognize that valence electrons are the electrons in the outermost shell (highest principal quantum number). For aluminum, this is the third shell (3s and 3p orbitals).
4. Count the electrons in the outermost shell: \$3s^2\( has 2 electrons and \)3p^1$ has 1 electron, totaling 3 valence electrons.
5. Conclude that a neutral aluminum atom has 3 valence electrons.