How many valence electrons are in a neutral lithium atom (Li)?

• A. 3
• B. 1
• C. 7
• D. 2

Answer: (B)

Verified step by step guidance

1. Identify the atomic number of lithium (Li), which is 3. This means a neutral lithium atom has 3 protons and 3 electrons.
2. Recall that valence electrons are the electrons in the outermost shell (energy level) of an atom.
3. Determine the electron configuration of lithium. The first shell (1s) can hold 2 electrons, so the first 2 electrons fill the 1s orbital.
4. The remaining electron goes into the second shell (2s), which is the outermost shell for lithium.
5. Conclude that lithium has 1 valence electron because there is only one electron in its outermost shell.