Write the electron configurations for the following ions,...

Write the electron configurations for the following ions, and determine which have noble-gas configurations: (a) $\mathrm{Co}^{2+}$,
(b) $\mathrm{Sn}^{2+}$,
(c) $\mathrm{Zr}^{4+}$,
(d) $\mathrm{Ag}^{+}$,
(e) $\mathrm{S}^{2-}$.

Key Concepts

Ion Formation and Electron Removal

Forming ions involves either removing or adding electrons from a neutral atom, leading to cations or anions, respectively. The process of electron removal, particularly for cations, typically follows the reverse order of orbital filling. This concept is key to determining the electron configuration of ions and understanding changes in chemical behavior when atoms become charged.

Noble-Gas Configuration

A noble-gas configuration refers to an electron arrangement that matches that of a noble gas, characterized by full valence shells and a high level of stability. Ions that achieve such configurations are especially stable, and recognizing these patterns helps in evaluating the relative stability and reactivity of different ions.

Electron Configuration

This concept describes the arrangement of electrons in an atom or ion’s orbitals according to energy levels. It is governed by principles like the Aufbau principle, Pauli exclusion principle, and Hund’s rule. Understanding electron configurations is essential for predicting chemical behavior and properties, as well as explaining periodic trends.

Transcript

00:01 This question asks us to write the electron configurations for the following ions and determine which have noble gas configurations.

00:08 So the first one is cobalt 2 plus.

00:11 Cobalt is right here, number 27 on the periodic table.

00:14 So in its ground state or in its non -ionic form, cobalt would have electron configuration of argon.

00:23 4s2, 3d7.

00:26 And so if this is cobalt 2 plus, we're going to remove two electrons.

00:30 We'll remove those from the 4s orbital.

00:32 Because it's higher energy than the 3d.

00:34 So if you take two away from the 4s, we're just left with the 7d electrons.

00:39 So electron configuration is argon, 3d7.

00:51 Okay, next is 102 plus.

00:55 10 is right here.

00:57 It does have an atomic number of 50.

01:01 Its normal electron configuration is krypton, 5s2, 4d, d10 for 5p2 so one more time 5s2 krypton 5s2 4d10 5p2 and if we're going to take two electrons away we're going to take them away from the p orbitals the 5p orbitals those are higher in energy than the 5 s's which are higher in energy than the 4 d's so tin 2 plus would have the electron configuration of krypton 5 s2 4 d10 then we have zirconium 4 plus zirconium is atomic number 40.

01:54 So normally its electron configuration is krypton 5s2, 4d2.

02:02 And if we're going to remove four electrons, we remove them from the s first, then the d...

Please give Ace some feedback