Question

1. zinc

a ar
b ar3d¹⁰
c ar4s²3d⁸
d ar4s²3d¹⁰4p²

Explanation:

Step1: Recall Zinc's Atomic Number

Zinc (Zn) has an atomic number of 30. Argon (Ar) has an atomic number of 18, so we need to account for 30 - 18 = 12 more electrons.

Step2: Electron Configuration Rules

Electrons fill orbitals in the order: \(1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, \dots\). The \(4s\) orbital fills before \(3d\), but for transition metals (and zinc, a d - block element), when writing the condensed configuration (using the noble gas core, [Ar] here), we write the \(3d\) orbitals after \(4s\) once electrons are in \(3d\).
The electron configuration of Zn is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}\). In condensed form (using [Ar] as the noble gas core, since Ar has the configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}\)), we replace the first 18 electrons with [Ar]. Then we have the remaining electrons: \(4s^{2}3d^{10}\)? Wait, no, actually, when writing the condensed configuration for d - block elements, the correct way is to write the \(3d\) orbitals after the noble gas core, and for Zn, the full configuration is \([Ar]4s^{2}3d^{10}\)? Wait, no, let's correct. The filling order: \(4s\) fills first, then \(3d\). But when we write the electron configuration for Zn, the \(4s\) electrons are still there, but in the condensed form, for transition metals, sometimes the \(3d\) is written before \(4s\) when \(3d\) is filled? Wait, no, the correct condensed electron configuration for Zn is \([Ar]3d^{10}4s^{2}\)? Wait, no, I made a mistake. Wait, the atomic number of Zn is 30. Ar is 18. So 30 - 18 = 12 electrons. The order of filling: \(4s\) (2 electrons), then \(3d\) (10 electrons, since 2 + 10 = 12). So the electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}\). When we use the noble gas core [Ar] (which is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}\)), the remaining electrons are \(4s^{2}3d^{10}\). But wait, the options: Option B is \([Ar]3d^{10}\), Option C is \([Ar]4s^{2}3d^{8}\), Option D is \([Ar]4s^{2}3d^{10}4p^{2}\), Option A is [Ar]. Wait, no, I think I messed up the filling order for the condensed configuration. Wait, actually, for zinc, the correct electron configuration is \([Ar]3d^{10}4s^{2}\)? No, that's not right. Wait, let's check the electron configuration of Zn. The atomic number is 30. So electrons: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰. So when writing the condensed form with [Ar] (which is 1s² 2s² 2p⁶ 3s² 3p⁶), we have 4s² 3d¹⁰ left? But the options don't have that. Wait, the options: Option B is [Ar]3d¹⁰, Option C is [Ar]4s²3d⁸, Option D is [Ar]4s²3d¹⁰4p², Option A is [Ar]. Wait, maybe I made a mistake in the filling order. Wait, actually, for transition metals, when the \(3d\) orbitals are filled, the \(4s\) electrons are still there, but in some cases, when writing the electron configuration for the atom, the \(3d\) is written before \(4s\) when \(3d\) is filled? No, that's not the case. Wait, no, the correct electron configuration for Zn is \([Ar]4s^{2}3d^{10}\)? But the options: Option B is [Ar]3d¹⁰, which is missing the 4s²? Wait, no, maybe the question is about the ion? Wait, no, the question is about Zinc (the atom). Wait, maybe I made a mistake. Wait, let's check the atomic number again. Zn: 30. Ar: 18. So 30 - 18 = 12 electrons. The electron configuration should be \(4s^{2}3d^{10}\) (since 4s can hold 2, 3d can hold 10; 2 + 10 = 12). But the options: Option B is [Ar]3d¹⁰, Option C is [Ar]4s²3d⁸, Option D is [Ar]4s²3d¹⁰4p², Option A is [Ar]. Wait, maybe the question is about the Zn²⁺ ion? Wait, if it's the Zn atom, then the correct configuration is \([Ar]4s^{2}3d^{10}\), but that's not one of the options. Wait, the options: Option B is [Ar]3d¹⁰, Option C is [Ar]4s²3d⁸, Option D is [Ar]4s²3d¹⁰4p², Option A is [Ar]. Wait, maybe I messed up the filling order. Wait, the \(3d\) orbitals fill after \(4s\), but for Zn, the \(3d\) is fully filled (10 electrons), and the \(4s\) has 2 electrons. But in the options, maybe the question is considering the electron configuration where the \(4s\) electrons are lost? No, Zn atom has 4s²3d¹⁰. Wait, the options: Let's re - evaluate. Option B: [Ar]3d¹⁰. If we consider that for Zn, when writing the electron configuration, sometimes the \(4s\) electrons are considered as part of the valence, but no. Wait, maybe the question has a typo, or I made a mistake. Wait, the atomic number of Zn is 30. Ar is 18. So the number of electrons after Ar is 12. The electron configuration should be \(4s^{2}3d^{10}\) (since 4s holds 2, 3d holds 10; 2 + 10 = 12). But the options: Option B is [Ar]3d¹⁰ (which is 18+10 = 28 electrons, missing 2), Option C is [Ar]4s²3d⁸ (18 + 2+8 = 28, missing 2), Option D is [Ar]4s²3d¹⁰4p² (18+2 + 10+2 = 32, too many), Option A is [Ar] (18, too few). Wait, this is confusing. Wait, maybe the question is about the Zn²⁺ ion. Zn²⁺ loses the 2 \(4s\) electrons, so its electron configuration is \([Ar]3d^{10}\), which is Option B. Ah, that must be it. So if it's the Zn²⁺ ion, then it loses the 4s² electrons, so the configuration is [Ar]3d¹⁰.

Answer:

B. \([Ar]3d^{10}\)