Chapter 6, Problem 6.104MP

Interpretation Introduction

(a)

Interpretation:

Electronic configuration of $\text{Fe}$, ${\text{Fe}}^{2+}$ and ${\text{Fe}}^{3+}$ should be determined.

Concept introduction:

Electronic configuration is the distribution of electrons in various atomic orbitals of the atom. These electrons follow some principles in order to be filled in orbitals. These are the Aufbau principle, Hund’s rule and Pauli’s exclusion principle. Aufbau principle states that electrons are filled in 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 pairing will not start until each orbital is singly occupied. Pauli’s exclusion principle states that spin of two electrons in one orbital can never be same.

Interpretation Introduction

(b)

Interpretation:

Values of $n$ and $l$ quantum numbers of the removed electron from ${\text{Fe}}^{2+}$ to ${\text{Fe}}^{3+}$ should be determined.

Concept introduction:

Numbers that give complete information about electron are quantum numbers. Following are four quantum numbers as follows:

1. Principal quantum number: It is denoted by $n$. It gives information about the shell of an electron.

2. Azimuthal quantum number: It is denoted by $l$. It gives information about the subshell of electrons. Different values of $l$ for different orbitals is as follows:

$\begin{array}{ccccc}l& 0& 1& 2& 3\\ \text{Orbital}& s& p& d& f\end{array}$

3. Magnetic quantum number: It is denoted by $m_l$. It gives information about orbitals present in the subshell. Its value ranges from $l$ to $-l$ including 0.

4. Spin quantum number: It is denoted by $m_s$. It tells about the spin of the electron and its value can either be $+\frac{\text{1}}{\text{2}}$ or $-\frac{\text{1}}{\text{2}}$.

Interpretation Introduction

(c)

Interpretation:

The longest wavelength of light that could ionize ${\text{Fe}}^{2+}$ to ${\text{Fe}}^{3+}$ should be determined.

Concept introduction:

Energy is directly related to the frequency and is expressed by the Planck-Einstein equation as follows:

$E=h\nu$

Where,

• $E$ is energy.
• $h$ is Planck’s constant.
• $\nu$ is frequency.

The relation between frequency and wavelength is expressed as follows:

$\nu =\frac{c}{\lambda }$

Where,

• $c$ is speed of light.
• $\lambda$ is wavelength of light.
• $\nu$ is frequency of light.

Planck-Einstein equation then modifies as follows:

$E=\frac{hc}{\lambda }$

d)

Interpretation Introduction

Interpretation:

Reason for less third ionization energy of $\text{Ru}$ than that of $\text{Fe}$ should be determined.

Concept introduction:

Ionization energy is the energy needed for the removal of an electron from an isolated, neutral and gaseous atom. It is denoted by $E_{\text{i}}$. The energy needed for removal of the first electron from a neutral atom is first ionization energy, represented by $E_{\text{i1}}$. The energy needed for removal of an electron from monoatomic cation is second ionization energy $\left(E_{\text{i2}}\right)$.