Chapter 8, Problem 8.33QE

(a)

Interpretation Introduction

Interpretation:

The cation with the electron configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^1$ and $1+$ charge has to be determined.

Concept Introduction:

The electronic configuration is defined as the distribution of electrons in various atomic orbitals of the atom. The electrons that are present in an outermost orbital are known as valence electrons whereas those present in the orbitals with lower quantum numbers are called core electrons. The general outer electronic configuration of $s\text{block}$ elements is $n{s}^{1-2}$, that of $p\text{block}$ elements is $n{s}^{2}n{p}^{1-6}$, that of $d-\text{block}$ elements is $\left(n-1\right)d^{1-10}n{s}^{0-2}$ and that of $f\text{block}$ elements is $\left(n-2\right)f^{1-14}\left(n-1\right)d^{0-10}n{s}^2$.

Electrons are filled in orbitals in accordance with three rules: Aufbau principle, Hund’s rule, and Pauli’s exclusion principle. Aufbau principle states that electrons are filled in the orbitals from lower to higher energy level as follows:

  $1s<2s<2p<3s<3p<4s<3d<4p<5s<4d<5p<6s<4f<5d<6p<7s$

Hund’s rule states that initially each orbital is singly occupied and then pairing occurs and Pauli’s exclusion principle states that the spin of two electrons in one orbital is always different.

Explanation of Solution

The electron configuration of the given ion is $1s^{2}2s^{2}2p^{6}3s^{2}3p^1$. Since this ion has a charge of $1+$, it is formed by the removal of one electron from the valence shell of the neutral atom. The electron configuration of the neutral atom is $1s^{2}2s^{2}2p^{6}3s^{2}3p^2$. It has a total of 14 electrons so its atomic number is 14. According to the periodic table, the element with atomic number 14 is silicon $\left(\text{Si}\right)$ so the ion with $1+$ charge is ${\text{Si}}^{+}$.

(b)

Interpretation Introduction

Interpretation:

The cation with the electron configuration $1s^{2}2s^{2}2p^{6}3s^1$ and $1+$ charge has to be determined.

Concept Introduction:

Refer to part (a).

Explanation of Solution

The electron configuration of the given ion is $1s^{2}2s^{2}2p^{6}3s^1$. Since this ion has a charge of $1+$, it is formed by the removal of one electron from the valence shell of the neutral atom. The electron configuration of the neutral atom is $1s^{2}2s^{2}2p^{6}3s^2$. It has a total of 12 electrons so its atomic number is 12. According to the periodic table, the element with atomic number 12 is magnesium $\left(\text{Mg}\right)$ so the ion with $1+$ charge is ${\text{Mg}}^{+}$.

(c)

Interpretation Introduction

Interpretation:

The cation with the electron configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}$ and $1+$ charge has to be determined.

Concept Introduction:

Refer to part (a).

Explanation of Solution

The electron configuration of the given ion is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}$. Since this ion has a charge of $1+$, it is formed by the removal of one electron from the valence shell of the neutral atom. The electron configuration of the neutral atom is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^1$. It has a total of 31 electrons so its atomic number is 31. According to the periodic table, the element with atomic number 31 is gallium $\left(\text{Ga}\right)$ so the ion with $1+$ charge is ${\text{Ga}}^{+}$.