What is the electronic configuration of a neutral sodium atom (atomic number 11)?
Answer and explanation
Correct answer: B. 1s² 2s² 2p⁶ 3s¹
- Step 1: Fill orbitals in order of energy: 2 + 2 + 6 = 10 electrons, and the eleventh goes into 3s. Answer: 1s² 2s² 2p⁶ 3s¹. Why not the others: 1s² 2s² 2p⁶ 3s², 1s² 2s² 2p⁵ 3s² and 1s² 2s² 2p⁶ 3p¹ don't fit.
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