Chapter 6, Problem 69A

(a)

Interpretation Introduction

Interpretation: The element having the outermost electron in $7s^1$ is to be identified.

Concept introduction:

The electron configuration of an element defines how its electrons are arranged throughout its atomic orbitals. Standard notation is used to represent atomic electron configurations, placing all electron-containing atomic subshells in sequential order. The number of electrons held by the subshell is indicated by superscript.

Answer to Problem 69A

Element is francium

Explanation of Solution

Given outermost electronic configuration is,

  $7s^1$

The last electron enters $7s^1$ which means the element belongs to the 7^th period and one electron is present in its outermost shell. Therefore, the element belongs to the 7^th period and group 1.

Thus, the element is Francium (Fr) having electronic configuration 87. Its electronic configuration is,

  $\text{Fr}:\left[\text{Rn}\right]7s^1$

(b)

Interpretation Introduction

Interpretation: The element in which only one electron is present in the d orbital is to be identified.

Concept introduction:

The electron configuration of an element defines how its electrons are arranged throughout its atomic orbitals. Standard notation is used to represent atomic electron configurations, placing all electron-containing atomic subshells in sequential order. The number of electrons held by the subshell is indicated by superscript.

Answer to Problem 69A

Scandium

Explanation of Solution

The element in which only one electron is present in the d orbital is scandium. Its atomic number is 21 and the electronic configuration is as shown:

  $\text{Sc}:1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^1$

Thus, the element is scandium.