Chapter 8, Problem 8.35QE

(a)

Interpretation Introduction

Interpretation:

The anion with the electron configuration $\left[\text{Ar}\right]4s^{2}3d^{10}4p^6$ and $2-$ 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.

Answer to Problem 8.35QE

The anion with the electron configuration $\left[\text{Ar}\right]4s^{2}3d^{10}4p^6$ and $2-$ charge is ${\text{Se}}^{2-}$.

Explanation of Solution

The electron configuration of the given ion is $\left[\text{Ar}\right]4s^{2}3d^{10}4p^6$. Since this ion has a charge of $2-$, it is formed by the gain of two electrons in the valence shell of the neutral atom. The electron configuration of the neutral atom is $\left[\text{Ar}\right]4s^{2}3d^{10}4p^4$. It has a total of 34 electrons so its atomic number is 34. According to the periodic table, the element with atomic number 34 is selenium $\left(\text{Se}\right)$ so the anion with $2-$ charge is ${\text{Se}}^{2-}$.

(b)

Interpretation Introduction

Interpretation:

The anion with the electron configuration $1s^{2}2s^{2}2p^5$ and $2-$ charge has to be determined.

Concept Introduction:

Refer to part (a).

Answer to Problem 8.35QE

The anion with the electron configuration $1s^{2}2s^{2}2p^5$ and $2-$ charge is ${\text{N}}^{2-}$.

Explanation of Solution

The electron configuration of the given ion is $1s^{2}2s^{2}2p^5$. Since this ion has a charge of $2-$, it is formed by the gain of two electrons in the valence shell of the neutral atom. The electron configuration of the neutral atom is $1s^{2}2s^{2}2p^3$. It has a total of 7 electrons so its atomic number is 7. According to the periodic table, the element with atomic number 7 is nitrogen $\left(\text{N}\right)$ so the anion with $2-$ charge is ${\text{N}}^{2-}$.

(c)

Interpretation Introduction

Interpretation:

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

Concept Introduction:

Refer to part (a).

Answer to Problem 8.35QE

The anion with the electron configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^6$ and $2-$ charge is ${\text{S}}^{2-}$.

Explanation of Solution

The electron configuration of the given ion is $1s^{2}2s^{2}2p^{6}3s^{2}3p^6$. Since this ion has a charge of $2-$, it is formed by the gain of two electrons in the valence shell of the neutral atom. The electron configuration of the neutral atom is $1s^{2}2s^{2}2p^{6}3s^{2}3p^4$. It has a total of 16 electrons so its atomic number is 16. According to the periodic table, the element with atomic number 16 is sulfur $\left(\text{S}\right)$ so the anion with $2-$ charge is ${\text{S}}^{2-}$.