Chapter 4, Problem 77E

Interpretation Introduction

(a)

Interpretation:

The electron configuration of $\text{He}$ is to be stated.

Concept introduction:

The elements in a modern periodic table are arranged in increasing order according to their atomic number. In the modern periodic table, the horizontal rows are known as periods, and the vertical columns are known as groups. There are seven periods and eighteen groups in the modern periodic table.

Answer to Problem 77E

The electron configuration of $\text{He}$ is ${\text{1s}}^{\text{2}}$.

Explanation of Solution

The chemical name of $\text{He}$ is helium. The atomic number of helium is two. The atomic number of helium indicates that the two electrons are present in it.

Electronic configuration tells about the arrangement of an electron in each subshell and orbit of an atom. Therefore, the electronic configuration of helium is ${\text{1s}}^{\text{2}}$. It can also be represented as $2$ in the form of shells.

Conclusion

The electron configuration of $\text{He}$ is ${\text{1s}}^{\text{2}}$.

Interpretation Introduction

(b)

Interpretation:

The electron configuration of $\text{Be}$ is to be stated.

Concept introduction:

The elements in a modern periodic table are arranged in increasing order according to their atomic number. In the modern periodic table, the horizontal rows are known as periods, and the vertical columns are known as groups. There are seven periods and eighteen groups in the modern periodic table.

Answer to Problem 77E

The electron configuration of $\text{Be}$ is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}$.

Explanation of Solution

The chemical name of $\text{Be}$ is beryllium. The atomic number of beryllium is four. The atomic number of beryllium indicates that four electrons are present in it.

Electronic configuration tells about the arrangement of an electron in each subshell and orbit of an atom. Therefore, the electronic configuration of beryllium is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}$. It can also be represented as $2,2$ in the form of shells.

Conclusion

The electron configuration of $\text{Be}$ is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}$.

Interpretation Introduction

(c)

Interpretation:

The electron configuration of $\text{Co}$ is to be stated.

Concept introduction:

The elements in a modern periodic table are arranged in increasing order according to their atomic number. In the modern periodic table, the horizontal rows are known as periods, and the vertical columns are known as groups. There are seven periods and eighteen groups in the modern periodic table.

Answer to Problem 77E

The electron configuration of $\text{Co}$ is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^{\text{6}}{\text{4s}}^{\text{2}}{\text{3d}}^{\text{7}}$.

Explanation of Solution

The chemical name of $\text{Co}$ is cobalt. The atomic number of cobalt is $27$. The atomic number of cobalt indicates that $27$ electrons are present in it.

Electronic configuration tells about the arrangement of an electron in each subshell and orbit of an atom. Therefore, the electronic configuration of cobalt is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^{\text{6}}{\text{4s}}^{\text{2}}{\text{3d}}^{\text{7}}$. It can also be represented as $2,2,6,2,6,2,7$ in the form of shells.

Conclusion

The electron configuration of $\text{Co}$ is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^{\text{6}}{\text{4s}}^{\text{2}}{\text{3d}}^{\text{7}}$.

Interpretation Introduction

(d)

Interpretation:

The electron configuration of $\text{Cd}$ is to be stated.

Concept introduction:

The elements in a modern periodic table are arranged in increasing order according to their atomic number. In the modern periodic table, the horizontal rows are known as periods, and the vertical columns are known as groups. There are seven periods and eighteen groups in the modern periodic table.

Answer to Problem 77E

The electron configuration of $\text{Cd}$ is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^{\text{6}}{\text{4s}}^{\text{2}}{\text{3d}}^{10}{\text{4p}}^{\text{6}}{\text{5s}}^{\text{2}}{\text{4d}}^{\text{10}}$.

Explanation of Solution

The chemical name of $\text{Cd}$ is cadmium. The atomic number of cadmium is $27$. The atomic number of cadmium indicates that $27$ electrons are present in it.

Electronic configuration tells about the arrangement of an electron in each subshell and orbit of an atom. Therefore, the electronic configuration of cadmium is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^{\text{6}}{\text{4s}}^{\text{2}}{\text{3d}}^{10}{\text{4p}}^{\text{6}}{\text{5s}}^{\text{2}}{\text{4d}}^{\text{10}}$. It can also be represented as $2,2,6,2,6,2,10,6,2,10$ in the form of shells.

Conclusion

The electron configuration of $\text{Cd}$ is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^{\text{6}}{\text{4s}}^{\text{2}}{\text{3d}}^{10}{\text{4p}}^{\text{6}}{\text{5s}}^{\text{2}}{\text{4d}}^{\text{10}}$.