Chapter 7, Problem 7.76QP

The ground-state electron configurations listed here are incorrect. Explain what mistakes have been made in each and write the correct electron configurations.

Al: 1s²2s²2p⁴3s²3p³

B: 1s²2s²2p⁵

F: 1s²2s²2p⁶

Interpretation Introduction

Interpretation:

The ground-state electron configurations of the given elements whose configurations made incorrect should be corrected.

Concept Introduction:

An orbital is an area of space in which electrons are orderly filled.  The maximum capacity in any type of orbital is two electrons.  An atomic orbital is defined as the region of space in which the probability of finding the electrons is highest.  It is subdivided into four orbitals such as $s,p,dandf$ orbitals which depend upon the number of electrons present in the nucleus of a particular atom.

There are three basic principles in which orbitals are filled by the electrons.

1. 1. Aufbau principle: In German, the word 'aufbau' means 'building up'.  The electrons are arranged in various orbitals in the order of increasing energies.
2. 2. Pauli exclusion principle: An electron does not have all the four quantum numbers.
3. 3. Hund’s rule: Each orbital is singly engaged with one electron having the maximum same spin capacity after that only pairing occurs.

The electron configuration is the allocation of electrons of an atom in atomic orbitals.  Electronic configuration of a particular atom is written by following the three basic principles.

To find: Correct the ground-state electron configuration of $\text{Al}$ whose configuration made incorrect as $1s^{2}2s^{2}2p^{4}3s^{2}3p^3$

Answer to Problem 7.76QP

(a)

The correct ground-state electron configuration of  whose configuration made incorrect as  $1s^{2}2s^{2}2p^{4}3s^{2}3p^3$ is $1s^{2}2s^{2}2p^{6}3s^{2}3p^1$

Explanation of Solution

$\text{Al}$ is placed in IIIA group of the periodic table.  Its atomic number is 13.  Therefore, $\text{Al}$ has 13 electrons in its shells.  $\text{Al}$ is a $p$-block element.  So, its outermost electrons are located in a $p$-subshell. 

All the 13 electrons are placed in the atomic orbitals by following Aufbau principle, Pauli exclusion principle and Hund’s rule.

All the 13 electrons of $\text{Al}$ occupy the atomic orbitals from lowest energy to highest energy orbitals.  The maximum capacity of each orbital has two electrons which have opposite spins.  $s$-atomic orbitals have a single shell whereas $p$-atomic orbitals have three sub-shells.  The 13 electrons are going into the $1s$-atomic orbitals first, followed by $2s,2p$-atomic orbitals which are again followed by $3s,3p$-atomic orbitals.  Blue colored orbital corresponds to $s$-atomic orbital.  Red colored orbital corresponds to $p$-atomic orbitals.

There are two electrons present in each $1s,2s,3s$-atomic orbitals, six electrons in $2p$-atomic orbital and one electron in $3p$-atomic orbital.  Therefore, the ground-state electron configuration of $\text{Al}$ is $1s^{2}2s^{2}2p^{6}3s^{2}3p^1$.  But, $1s^{2}2s^{2}2p^{4}3s^{2}3p^3$ is incorrectly given.  Here, $p$-orbital isn’t filled completely.

Interpretation Introduction

Interpretation:

The ground-state electron configurations of the given elements whose configurations made incorrect should be corrected.

Concept Introduction:

An orbital is an area of space in which electrons are orderly filled.  The maximum capacity in any type of orbital is two electrons.  An atomic orbital is defined as the region of space in which the probability of finding the electrons is highest.  It is subdivided into four orbitals such as $s,p,dandf$ orbitals which depend upon the number of electrons present in the nucleus of a particular atom.

There are three basic principles in which orbitals are filled by the electrons.

1. 1. Aufbau principle: In German, the word 'aufbau' means 'building up'.  The electrons are arranged in various orbitals in the order of increasing energies.
2. 2. Pauli exclusion principle: An electron does not have all the four quantum numbers.
3. 3. Hund’s rule: Each orbital is singly engaged with one electron having the maximum same spin capacity after that only pairing occurs.

The electron configuration is the allocation of electrons of an atom in atomic orbitals.  Electronic configuration of a particular atom is written by following the three basic principles.

To find: Correct the ground-state electron configuration of B whose configuration made incorrect as $1s^{2}2s^{2}2p^5$

Answer to Problem 7.76QP

 (b)

The correct ground-state electron configuration of $\text{B}$ whose configuration made incorrect as $1s^{2}2s^{2}2p^5$ is $1s^{2}2s^{2}2p^1$

Explanation of Solution

$\text{B}$ is placed in IIIA group of the periodic table.  Its atomic number is 5.  Therefore, $\text{B}$ has 5 electrons in its shells.  $\text{B}$ is a $p$-block element.  So, its outermost electrons are located in a $p$-subshell. 

All the 5 electrons are placed in the atomic orbitals by following Aufbau principle, Pauli exclusion principle and Hund’s rule.

All the 5 electrons of $\text{B}$ occupy the atomic orbitals from lowest energy to highest energy orbitals.  The maximum capacity of each orbital has two electrons which have opposite spins.  $s$-atomic orbitals have a single shell whereas $p$-atomic orbitals have three sub-shells.  The 5 electrons are going into the $1s$-atomic orbitals first, followed by $2s,2p$-atomic orbitals.  Blue colored orbital corresponds to $s$-atomic orbital.  Red colored orbital corresponds to $p$-atomic orbitals.

There are two electrons present in each $1s,2s$-atomic orbitals, one electron in $2p$-atomic orbital.  Therefore, the ground-state electron configuration of $\text{B}$ is $1s^{2}2s^{2}2p^1$.  But, $1s^{2}2s^{2}2p^5$ is given incorrectly.  Here, 9 electrons are present but $\text{B}$ has only 5 electrons.

Interpretation Introduction

Interpretation:

The ground-state electron configurations of the given elements whose configurations made incorrect should be corrected.

Concept Introduction:

An orbital is an area of space in which electrons are orderly filled.  The maximum capacity in any type of orbital is two electrons.  An atomic orbital is defined as the region of space in which the probability of finding the electrons is highest.  It is subdivided into four orbitals such as $s,p,dandf$ orbitals which depend upon the number of electrons present in the nucleus of a particular atom.

There are three basic principles in which orbitals are filled by the electrons.

1. 1. Aufbau principle: In German, the word 'aufbau' means 'building up'.  The electrons are arranged in various orbitals in the order of increasing energies.
2. 2. Pauli exclusion principle: An electron does not have all the four quantum numbers.
3. 3. Hund’s rule: Each orbital is singly engaged with one electron having the maximum same spin capacity after that only pairing occurs.

The electron configuration is the allocation of electrons of an atom in atomic orbitals.  Electronic configuration of a particular atom is written by following the three basic principles.

To find: Correct the ground-state electron configuration of F whose configuration made incorrect as $1s^{2}2s^{2}2p^6$

Answer to Problem 7.76QP

(c)

The correct ground-state electron configuration of $\text{F}$ whose configuration made incorrect as $1s^{2}2s^{2}2p^6$ is $1s^{2}2s^{2}2p^5$

Explanation of Solution

$\text{F}$ is placed in VIIA group of the periodic table.  Its atomic number is 9.  Therefore, $\text{F}$ has 9 electrons in its shells.  $\text{F}$ is a $p$-block element.  So, its outermost electrons are located in a $p$-subshell. 

All the 9 electrons are placed in the atomic orbitals by following Aufbau principle, Pauli exclusion principle and Hund’s rule.

All the 9 electrons of $\text{F}$ occupy the atomic orbitals from lowest energy to highest energy orbitals.  The maximum capacity of each orbital has two electrons which have opposite spins.  $s$-atomic orbitals have a single shell whereas $p$-atomic orbitals have three sub-shells.  The 9 electrons are going into the $1s$-atomic orbitals first, followed by $2s,2p$-atomic orbitals.  Blue colored orbital corresponds to $s$-atomic orbital.  Red colored orbital corresponds to $p$-atomic orbitals.

There are two electrons present in each $1s,2s$-atomic orbitals, five electrons in $2p$-atomic orbital.  Therefore, the ground-state electron configuration of $\text{F}$ is $1s^{2}2s^{2}2p^5$.  But, $1s^{2}2s^{2}2p^6$ is incorrectly given.  Here, 10 electrons are present but $\text{F}$ has only 9 electrons.