Chapter 12, Problem 2E

A monoatomic ion with a charge of $1-$ has an electronic configuration of $1s^{2}2s^{2}2p^{6}3s^{2}3p^6$. (a) Is this ion a cation or an anion? (b) With what noble gas is it isolectronic? (c) What is the symbol of the ion?

Interpretation Introduction

(a)

Interpretation:

Whether the monoatomic ion with a charge of $1-$ that has an electronic configuration of $1s^{2}2s^{2}2p^{6}3s^{2}3p^6$ is a cation or anion is to be stated.

Concept introduction:

The arrangement of electrons in the energy sublevels is explained by the electron configuration of an atom. The electron configuration of an atom can be written according to the arrangement of energy levels as shown below.

$1\text{s}<2\text{s}<2\text{p}<3\text{s}<3\text{p}<4\text{s}<3\text{d}<4\text{p}<5\text{s}<4\text{d}<5\text{p}<6\text{s}$

In the modern periodic table, the horizontal rows are known as periods, whereas vertical columns are known as groups. There are $7$ periods and $18$ groups in a modern periodic table.

Answer to Problem 2E

The monoatomic ion with a charge of $1-$ that has an electronic configuration of $1s^{2}2s^{2}2p^{6}3s^{2}3p^6$ is an anion.

Explanation of Solution

The monoatomic ion with a charge of $1-$ has an electronic configuration of $1s^{2}2s^{2}2p^{6}3s^{2}3p^6$. The electronic configuration indicates chlorine, $\text{Cl}$ element. Here, $\text{Cl}$ gains $1$ electron to form the resulting anion, ${\text{Cl}}^{-}$.

Conclusion

The monoatomic ion with a charge of $1-$ that has an electronic configuration of $1s^{2}2s^{2}2p^{6}3s^{2}3p^6$ is an anion.

Interpretation Introduction

(b)

Interpretation:

The noble gas with which the monoatomic ion is isolectronic is to be stated.

Concept introduction:

The arrangement of electrons in the energy sublevels is explained by the electron configuration of an atom. The electron configuration of an atom can be written according to the arrangement of energy levels as shown below.

$1\text{s}<2\text{s}<2\text{p}<3\text{s}<3\text{p}<4\text{s}<3\text{d}<4\text{p}<5\text{s}<4\text{d}<5\text{p}<6\text{s}$

In the modern periodic table, the horizontal rows are known as periods, whereas vertical columns are known as groups. There are $7$ periods and $18$ groups in a modern periodic table.

Answer to Problem 2E

The noble gas with which the monoatomic ion is isolectronic is argon, $\text{Ar}$.

Explanation of Solution

The electronic configuration of $\text{Cl}$ is $1s^{2}2s^{2}2p^{6}3s^{2}3p^5$. It can gain $1$ electron in the outermost shell. The resulting anion, ${\text{Cl}}^{-}$ is isoelectronic with argon, $\text{Ar}$.

The electronic configuration of ${\text{Cl}}^{-}$ is $1s^{2}2s^{2}2p^{6}3s^{2}3p^6$.

The electronic configuration of $\text{Ar}$ is $1s^{2}2s^{2}2p^{6}3s^{2}3p^6$.

Conclusion

The noble gas with which the monoatomic ion is isolectronic is argon, $\text{Ar}$.

Interpretation Introduction

(c)

Interpretation:

The symbol of the ion is to be stated.

Concept introduction:

The arrangement of electrons in the energy sublevels is explained by the electron configuration of an atom. The electron configuration of an atom can be written according to the arrangement of energy levels as shown below.

$1\text{s}<2\text{s}<2\text{p}<3\text{s}<3\text{p}<4\text{s}<3\text{d}<4\text{p}<5\text{s}<4\text{d}<5\text{p}<6\text{s}$

In the modern periodic table, the horizontal rows are known as periods, whereas vertical columns are known as groups. There are $7$ periods and $18$ groups in a modern periodic table.

Answer to Problem 2E

The symbol of the ion is ${\text{Cl}}^{-}$.

Explanation of Solution

Chlorine belongs to the halogen group. The atomic number of $\text{Cl}$ is $17$. It gains $1$ electron to form the anion. Therefore, the symbol of the ion is ${\text{Cl}}^{-}$.

Conclusion

The symbol of the ion is ${\text{Cl}}^{-}$.