In a simplified valence-electron model for main-group elements, how many valence electrons does beryllium (Be) have?

• A. 8
• B. 2
• C. 4
• D. 1

Answer: (B)

Verified step by step guidance

1. Identify the element in question, which is beryllium (Be).
2. Recall that the valence electrons are the electrons in the outermost shell (energy level) of an atom.
3. Determine the electron configuration of beryllium: its atomic number is 4, so it has 4 electrons.
4. Write the electron configuration for beryllium: \$1s^2 2s^2$.
5. Count the electrons in the outermost shell (the second shell, \$2s^2$), which gives the number of valence electrons for beryllium.