Question

for the electronic configuration given, choose the electronic configuration of the element that would match its chemical properties. select the single best answer.
1s² 2s² 2p⁶ 3s²
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s²
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁴
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d²
1s² 2s² 2p³

Explanation:

Step1: Recall electron configuration rules

Electron configurations follow the Aufbau principle (fill lower - energy orbitals first), Pauli exclusion principle, and Hund's rule. The order of filling is \(1s<2s < 2p<3s<3p<4s<3d<4p<5s<4d<5p\cdots\).

Step2: Analyze each option

• Option \(1s^{2}2s^{2}2p^{3}\): This is for an element with \(2 + 2+3=7\) electrons (Nitrogen).
• Option \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{4}\): For an element with \(2 + 2+6 + 2+6+2 + 10+4=34\) electrons (Selenium).
• Option \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{2}\): For an element with \(2+2 + 6+2+6+2+10+6+2+2 = 44\) electrons (Ruthenium).
• Option \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}\): For an element with \(2+2 + 6+2+6+2+10+6+2=42\) electrons (Molybdenum).

Answer:

\(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}\)