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Multiple Choice
How many principal energy levels are present in a neutral sodium (Na) atom?
A
1
B
2
C
4
D
3
Verified step by step guidance
1
Recall that the principal energy levels correspond to the main electron shells around the nucleus, labeled by the principal quantum number \(n = 1, 2, 3, \ldots\).
Determine the atomic number of sodium (Na), which is 11, meaning it has 11 electrons in its neutral state.
Write the electron configuration of sodium to see how electrons fill the energy levels: \$1s^2\ 2s^2\ 2p^6\ 3s^1$.
Identify the highest principal quantum number \(n\) in the electron configuration, which corresponds to the outermost shell occupied by electrons.
Conclude that the number of principal energy levels in a neutral sodium atom is equal to this highest \(n\) value.