Multiple Choice
Which of the following is the correct electron configuration for sodium (Na)?
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10. Periodic Properties of the Elements
The Electron Configuration
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Which of the following is the correct electron configuration for the N^{3-} anion?
A
1s^2 2s^2 2p^4
B
1s^2 2s^2 2p^3
C
1s^2 2s^2 2p^5
D
1s^2 2s^2 2p^6
Verified step by step guidance1
Step 1: Identify the atomic number of nitrogen (N). Nitrogen has an atomic number of 7, which means a neutral nitrogen atom has 7 electrons.
Step 2: Understand what the N^{3-} anion means. The 3- charge indicates that the nitrogen atom has gained 3 extra electrons, increasing the total number of electrons to 7 + 3 = 10.
Step 3: Write the electron configuration for 10 electrons. Start filling the orbitals in order of increasing energy: 1s, 2s, then 2p.
Step 4: Recall the maximum number of electrons each subshell can hold: 1s can hold 2, 2s can hold 2, and 2p can hold 6 electrons.
Step 5: Combine these to write the full electron configuration for N^{3-} as $1s^2 2s^2 2p^6$, which corresponds to the electron configuration of neon, a noble gas.
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