Question

which is the electron configuration for zinc? 1s²2s²2p⁶3s²3p⁶4s²3d⁸ 1s²2s²2p⁶3s²3p⁶4s¹3d¹⁰ 1s²2s²2p⁵3s²3p⁶4s²3d¹⁰ 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰

Explanation:

Step1: Determine the atomic number of zinc

Zinc has an atomic number \( Z = 30 \). This means a neutral zinc atom has 30 electrons.

Step2: Analyze the electron - filling rules

Electrons fill orbitals in the order \( 1s<2s<2p<3s<3p<4s<3d\). The \( 1s\) orbital can hold 2 electrons, \( 2s\) can hold 2 electrons, \( 2p\) can hold 6 electrons, \( 3s\) can hold 2 electrons, \( 3p\) can hold 6 electrons, \( 4s\) can hold 2 electrons, and \( 3d\) can hold 10 electrons.

• For the configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{8}\), the total number of electrons is \(2 + 2+6 + 2+6 + 2+8=28

eq30\).

• For the configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}3d^{10}\), the total number of electrons is \(2 + 2+6 + 2+6 + 1+10 = 29

eq30\).

• For the configuration \(1s^{2}2s^{2}2p^{5}3s^{2}3p^{6}4s^{2}3d^{10}\), the total number of electrons is \(2 + 2+5 + 2+6 + 2+10=29

eq30\).

• For the configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}\), the total number of electrons is \(2+2 + 6+2+6+2 + 10=30\). Also, according to the Aufbau principle, after filling \(3p\) orbitals, we fill \(4s\) before \(3d\) (because \(E_{4s}

Answer:

\(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}\) (the fourth option)