Chapter 19, Problem 1E

Write the electron configurations far each of the following elements:

(a) Sc.

(b) Ti.

(c) Cr.

(d) Fe.

(e) Ru

Interpretation Introduction

Interpretation: The electron configuration of Sc element should be determined.

Concept Introduction: Arrangement of electrons in the orbitals of an atom in an increasing order of energy of the orbital is said to be the electron configuration.

Answer to Problem 1E

  $Sc:\left[Ar\right]4s^{2}3d^1$

Explanation of Solution

The number of electrons present in an element in its neutral state is equal to the number of protons in that element and is said to be its atomic number, which is unique for every element. Arrangement of electrons in the orbitals of an atom in an increasing order of energy of the orbital is said to be the electron configuration.

Since, the atomic number of Sc is 21 so, the number of electrons in Sc is 21.

The electron configuration of Sc is:

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

  $Sc:\left[Ar\right]4s^{2}3d^1$

Interpretation Introduction

Interpretation: The electron configuration of Ti element should be determined.

Concept Introduction: Arrangement of electrons in the orbitals of an atom in an increasing order of energy of the orbital is said to be the electron configuration.

Answer to Problem 1E

  $Ti:\left[Ar\right]4s^{2}3d^2$

Explanation of Solution

The number of electrons present in an element in its neutral state is equal to the number of protons in that element and is said to be its atomic number, which is unique for every element. Arrangement of electrons in the orbitals of an atom in an increasing order of energy of the orbital is said to be the electron configuration.

Since, the atomic number of Ti is 22 so, the number of electrons in Ti is 22.

The electron configuration of Ti is:

  $\begin{array}{l}Ti:1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^2\hfill \\ Ti:\left[Ar\right]4s^{2}3d^2\hfill \\ \hfill \end{array}$

Interpretation Introduction

Interpretation: The electron configuration of Cr element should be determined.

Concept Introduction: Arrangement of electrons in the orbitals of an atom in an increasing order of energy of the orbital is said to be the electron configuration.

Answer to Problem 1E

  $Cr:\left[Ar\right]4s^{1}3d^5$

Explanation of Solution

The number of electrons present in an element in its neutral state is equal to the number of protons in that element and is said to be its atomic number, which is unique for every element. Arrangement of electrons in the orbitals of an atom in an increasing order of energy of the orbital is said to be the electron configuration.

Since, the atomic number of Cr is 24 so, the number of electrons in Cr is 24.

The electron configuration of Cr is:

  $\begin{array}{l}Cr:1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}3d^5\hfill \\ Cr:\left[Ar\right]4s^{1}3d^5\hfill \\ \hfill \end{array}$

Interpretation Introduction

Interpretation: The electron configuration of Fe element should be determined.

Concept Introduction: Arrangement of electrons in the orbitals of an atom in an increasing order of energy of the orbital is said to be the electron configuration.

Answer to Problem 1E

  $Fe:\left[Ar\right]4s^{2}3d^6$

Explanation of Solution

The number of electrons present in an element in its neutral state is equal to the number of protons in that element and is said to be its atomic number, which is unique for every element. Arrangement of electrons in the orbitals of an atom in an increasing order of energy of the orbital is said to be the electron configuration.

Since, the atomic number of Fe is 26 so, the number of electrons in Fe is 26.

The electron configuration of Fe is:

  $\begin{array}{l}Fe:1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^6\hfill \\ Fe:\left[Ar\right]4s^{2}3d^6\hfill \end{array}$

Interpretation Introduction

Interpretation: The electron configuration of Ru element should be determined.

Concept Introduction: Arrangement of electrons in the orbitals of an atom in an increasing order of energy of the orbital is said to be the electron configuration.

Answer to Problem 1E

  $Ru:\left[Kr\right]5s^{1}4d^7$

Explanation of Solution

The number of electrons present in an element in its neutral state is equal to the number of protons in that element and is said to be its atomic number, which is unique for every element. Arrangement of electrons in the orbitals of an atom in an increasing order of energy of the orbital is said to be the electron configuration.

Since, the atomic number of Ru is 44 so, the number of electrons in Ru is 44.

The electron configuration of Ru is:

  $\begin{array}{l}Ru:1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}4d^{7}5s^1\\ Ru:\left[Kr\right]5s^{1}4d^7\end{array}$