Chapter 1, Problem 1.40P

Interpretation Introduction

(a)

Interpretation:

The ground-state electron configuration of the aluminum atom is to be written. Valence electrons and core electrons in aluminum are to be stated.

Concept introduction:

The arrangement of electrons in atomic orbitals is called the atom’s ‘electron configuration’. The most stable electron configuration of an element is called the ‘ground state’ configuration. Valence electrons are the electrons occupying the highest energy shell while core electrons are the electrons occupying the remaining lower energy shells of an atom.

Answer to Problem 1.40P

For aluminum, the group-state electron configuration is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^1$. Aluminum has three valence electrons and ten core electrons.

Explanation of Solution

The atomic number of Aluminum is $\text{13}$. These $\text{13}$ electrons need to be distributed in atomic orbitals. According to the Aufbau’s principle, the first two electrons are placed in the $\text{1s}$ orbital. The next two go in the $\text{2s}$ orbital. Six electrons go in the 2p orbitals as pairs. The remaining three electrons are distributed in the 3s and 3p orbitals. The electron configuration is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^1$. The valence shell is the highest energy shell that is the third shell, so there are three electrons in the valence shell of aluminum. The remaining lower energy shells are known as the core-shells, so there are ten core electrons in aluminum.

Conclusion

Aluminum has three valence electrons and ten core electrons.

Interpretation Introduction

(b)

Interpretation:

The ground-state electron configuration of the sulfur atom is to be written. Valence electrons and core electrons in sulfur are to be stated.

Concept introduction:

The arrangement of electrons in atomic orbitals is called the atom’s ‘electron configuration’. The most stable electron configuration of an element is called the ‘ground state’ configuration. Valence electrons are the electrons occupying the highest energy shell while core electrons are the electrons occupying the remaining lower energy shells of an atom.

Answer to Problem 1.40P

For the sulfur atom, the ground-state electron configuration is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^4$. Sulfur has six valence electrons and ten core electrons.

Explanation of Solution

The atomic number of sulfur is $\text{16}$. These $\text{16}$ electrons need to be distributed in atomic orbitals. According to the Aufbau’s principle, the first two electrons are placed in the $\text{1s}$ orbital. The next two go in the $\text{2s}$ orbital. Six electrons are placed in the 2p orbitals. The remaining six electrons are distributed in the 3s and 3p orbitals. The electron configuration is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^4$. The valence shell is the highest energy shell that is the third shell, so there are six electrons in the valence shell of sulfur. The remaining lower energy shells are known as the core-shells, so there are ten core electrons in sulfur.

Conclusion

Sulfur has six valence electrons and ten core electrons.

Interpretation Introduction

(c)

Interpretation:

The ground-state electron configuration of the oxygen atom is to be written. Valence electrons and core electrons in oxygen are to be stated.

Concept introduction:

The arrangement of electrons in atomic orbitals is called the atom’s ‘electron configuration’. The most stable electron configuration of an element is called the ‘ground state’ configuration. Valence electrons are the electrons occupying the highest energy shell while core electrons are the electrons occupying the remaining lower energy shells of an atom.

Answer to Problem 1.40P

For the oxygen atom, the ground-state electron configuration is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{4}}$. Oxygen has six valence electrons and two core electrons.

Explanation of Solution

The atomic number of oxygen is $8$. These $8$ electrons need to be distributed in atomic orbitals. According to the Aufbau’s principle, the first two electrons are placed in the $\text{1s}$ orbital. The next two go in the $\text{2s}$ orbital. Four electrons go in the 2p orbitals. The electron configuration is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^4$. The valence shell is the highest energy shell that is the second shell, so there are six electrons in the valence shell of oxygen. The remaining lower energy shells are known as the core-shells, so there are two core electrons in oxygen.

Conclusion

Oxygen has six valence electrons and two core electrons.

Interpretation Introduction

(d)

Interpretation:

The ground-state electron configuration of the nitrogen atom is to be written. Valence electrons and core electrons in nitrogen are to be stated.

Concept introduction:

The arrangement of electrons in atomic orbitals is called the atom’s ‘electron configuration’. The most stable electron configuration of an element is called the ‘ground state’ configuration. Valence electrons are the electrons occupying the highest energy shell while core electrons are the electrons occupying the remaining lower energy shells of an atom.

Answer to Problem 1.40P

For the nitrogen atom, the ground-state electron configuration is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{3}}$. Nitrogen has five valence electrons and two core electrons.

Explanation of Solution

The atomic number of Nitrogen is $7$. These $7$ electrons need to be distributed in atomic orbitals. According to the Aufbau’s principle, the first two electrons are placed in the $\text{1s}$ orbital. The next two go in the $\text{2s}$ orbital, leaving one electron for each of the three $\text{2p}$ orbitals. The electron configuration is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{3}}$. The valence shell is the highest energy shell that is the second shell, so there are five electrons in the valence shell of nitrogen. The remaining lower energy shells are known as the core-shells, so there are two core electrons in nitrogen.

Conclusion

Nitrogen has five valence electrons and two core electrons.

Interpretation Introduction

(e)

Interpretation:

The ground-state electron configuration of the fluorine atom is to be written. Valence electrons and core electrons in fluorine are to be stated.

Concept introduction:

The arrangement of electrons in atomic orbitals is called the atom’s ‘electron configuration’. The most stable electron configuration of an element is called the ‘ground state’ configuration. Valence electrons are the electrons occupying the highest energy shell while core electrons are the electrons occupying the remaining lower energy shells of an atom.

Answer to Problem 1.40P

For the fluorine atom, the ground-state electron configuration is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{5}}$. Fluorine has seven valence electrons and two core electrons.

Explanation of Solution

The atomic number of fluorine is $9$. These $9$ electrons need to be distributed in atomic orbitals. According to the Aufbau’s principle, the first two electrons are placed in the $\text{1s}$ orbital. The next two go in the $\text{2s}$ orbital, leaving five electrons for the $\text{2p}$ orbitals. The electron configuration is ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{5}}$. The valence shell is the highest energy shell that is the second shell, so there are seven electrons in the valence shell of fluorine. The remaining lower energy shells are known as the core-shells, so there are two core electrons in fluorine.

Conclusion

Fluorine has seven valence electrons and two core electrons.