Which electron configuration is correct for a sodium ion (Na^+)?

• A. 1s^2 2s^2 2p^5
• B. 1s^2 2s^2 2p^6 3s^2
• C. 1s^2 2s^2 2p^6
• D. 1s^2 2s^2 2p^6 3s^1

Answer: (C)

Verified step by step guidance

1. Step 1: Identify the atomic number of sodium (Na), which is 11. This means a neutral sodium atom has 11 electrons.
2. Step 2: Write the electron configuration for neutral sodium: \$1s^2 2s^2 2p^6 3s^1$, accounting for all 11 electrons.
3. Step 3: Understand that a sodium ion with a +1 charge (Na\(^+\)) has lost one electron, so it now has 10 electrons.
4. Step 4: Remove one electron from the highest energy level (the 3s orbital) because electrons are lost from the outermost shell first. This leaves the configuration as \$1s^2 2s^2 2p^6$.
5. Step 5: Confirm that the resulting electron configuration corresponds to the electron configuration of neon (Ne), a noble gas with 10 electrons, which is stable and correct for Na\(^+\).