As you move down a group in the periodic table, what happens to the number of energy levels (principal quantum numbers) in the atoms?

• A. The number of energy levels decreases.
• B. The number of energy levels increases.
• C. The number of energy levels first increases, then decreases.
• D. The number of energy levels remains the same.

Answer: (B)

Verified step by step guidance

1. Recall that the periodic table is arranged in periods (rows) and groups (columns), where each period corresponds to a principal energy level (principal quantum number, n).
2. Understand that as you move down a group in the periodic table, you are moving from one period to the next lower period, which means the principal quantum number increases by 1 for each step down.
3. Recognize that the principal quantum number (n) represents the number of energy levels or shells in an atom, so moving down a group adds an additional energy level.
4. Therefore, the number of energy levels in the atoms increases as you move down a group because each element has electrons in a higher principal energy level than the one above it.
5. Summarize that the correct statement is: 'The number of energy levels increases' as you move down a group in the periodic table.