Which of the following atoms has the most valence electrons?

• A. O
• B. Be
• C. He
• D. N
• E. Si

Answer: (A)

Verified step by step guidance

1. Identify the group number of each element in the periodic table, as the group number often indicates the number of valence electrons for main group elements.
2. For Beryllium (Be), locate it in Group 2 of the periodic table, which means it has 2 valence electrons.
3. For Helium (He), locate it in Group 18, but note that it is an exception with only 2 valence electrons due to its full outer shell.
4. For Nitrogen (N), locate it in Group 15, which means it has 5 valence electrons.
5. For Silicon (Si), locate it in Group 14, which means it has 4 valence electrons. Compare these values to determine which element has the most valence electrons.