Chapter 2, Problem 2A.20E

(a)

Interpretation Introduction

Interpretation:

The expected ground-state electron configuration and number of unpaired electrons in ${\text{Sc}}^{3+}$ has to be given.

Concept Introduction:

In chemical reactions, only outer electrons are involved thus the electronic configuration is simplified when the core electrons are represented by the closest noble gases followed by valence electrons. For instance, nitrogen with atomic number seven is written as $\left[\text{He}\right]{\text{2s}}^{\text{2}}{\text{2p}}^3$.

The convention followed to remove or add electrons is electrons of largest principal quantum number are lost first. In case of subshells of the same $\text{n}$ value, electrons are lost from the subshell with highest $\text{l}$ value.

(b)

Interpretation Introduction

Interpretation:

The expected ground-state electron configuration and number of unpaired electrons in ${\text{Co}}^{2+}$ has to be given.

Concept Introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

The expected ground-state electron configuration and number of unpaired electrons in ${\text{Sr}}^{2+}$ has to be given.

Concept Introduction:

Refer to part (a).

(d)

Interpretation Introduction

Interpretation:

The expected ground-state electron configuration in ${\text{Se}}^{2-}$ and number of unpaired electrons has to be given.

Concept Introduction:

Refer to part (a).