Chapter 1, Problem 1E.12E

(a)

Interpretation Introduction

Interpretation:

The ground state configuration of titanium atom has to be predicted.

Concept introduction:

Electronic configuration: The electron configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbitals.

Electrons occupy the lowest energy orbitals. The increasing order of orbital energy is $s,p,dandf.$  The lowest energy orbital is $ls.$

The energy order of the orbital for the first three periods is as follows,

    $ls,2s,2p,3s,and3p.$

The orbital which is closer to the nucleus has lower energy; therefore the $2s$ is lower in energy than $3s.$   Accordingly $2s$ is lower in energy than $2pand4s$ is lower in energy than $3d.$

In general, the orbitals can hold maximum of two electrons, the two electrons must have opposite spin.

The subshell ordering by Aufbau principle is given below,

    $ls,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,7s,5f,6d,7p,8s,\mathrm{...}$

Explanation of Solution

The electronic configuration is depends on the electrons in the atom.  The titanium atom has $22$ electrons.

The subshell ordering by Aufbau principle is given below;

    $ls,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,7s,5f,6d,7p,8s,\mathrm{...}$

Therefore ground state electronic configuration of titanium atom is $l{s}^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^2$ $\left(22electrons\right).$

Titanium belongs to Period $4$ and Group $4.$  It has a argon core with additional four valence electron.

The electronic configuration also can be written as follows,

    $\left[Ar\right]4s^{2}3d^2.$

(b)

Interpretation Introduction

Interpretation:

The ground state configuration of chromium atom has to be predicted.

Concept introduction:

Refer to part (a).

Explanation of Solution

The electronic configuration is depends on the electrons in the atom.  The chromium atom has $24$ electrons.

The subshell ordering by Aufbau principle is given below;

    $ls,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,7s,5f,6d,7p,8s,\mathrm{...}$

Therefore ground state electronic configuration of chromium atom is $l{s}^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}3d^5$ $\left(24electrons\right).$

Chromium belongs to Period $4$ and Group $6.$  It has a argon core with four additional valence electrons.

The electronic configuration also can be written as follows,

    $\left[Ar\right]4s^{1}3d^5.$

(c)

Interpretation Introduction

Interpretation:

The ground state configuration of europium atom has to be predicted.

Concept introduction:

Refer to part (a).

Explanation of Solution

The electronic configuration is depends on the electrons in the atom.  The europium atom has $63$ electrons.

The subshell ordering by Aufbau principle is given below;

    $ls,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,7s,5f,6d,7p,8s,\mathrm{...}$

Therefore ground state electronic configuration of europium atom is $l{s}^{2}2s^{2}2p^{6}3s^{2}3p^{5}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^7$ $\left(63electrons\right).$

The electronic configuration also can be written as follows,

    $\left[Xe\right]{\text{ 4f}}^{\text{7}}{\text{ 6s}}^{\text{2}}.$

(d)

Interpretation Introduction

Interpretation:

The ground state configuration of krypton atom has to be predicted.

Concept introduction:

Refer to part (a).

Explanation of Solution

The electronic configuration is depends on the electrons in the atom.  The krypton atom has $36$ electrons.

The subshell ordering by Aufbau principle is given below;

    $ls,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,7s,5f,6d,7p,8s,\mathrm{...}$

Therefore ground state electronic configuration of rubidium atom is $l{s}^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^6$ $\left(36electrons\right).$

Rubidium belongs to Period $4$ and Group $18.$  It has argon core with eighteen additional valence electron.

The electronic configuration also can be written as follows,

    $\left[Ar\right]{\text{ 3d}}^{\text{10}}4s^{2}4p^6.$