Chapter U1, Problem C4.4RE

Interpretation Introduction

Interpretation: The electron configuration of aluminum should be written followed by noble gas shorthand configuration.

Concept introduction: The protons and neutrons of an atom are present in the nucleus of an atom whereas the electrons are always moving around the nucleus of an atom that is they possess kinetic energy. The lowest possible energy level of an electron in an atom is its ground state.

The electrons are arranged around the nucleus of an atom in an increasing order of energy levels and this description of orbitals of atom occupied by electrons is known as electronic configuration.

Answer to Problem C4.4RE

The electron configuration of aluminum is:

${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^{\text{1}}$

The noble gas shorthand configuration of Al is:

$\left[\text{Ne}\right]\text{ 3s² 3p¹}$

Explanation of Solution

The electrons are arranged around the nucleus of an atom in an increasing order of energy levels and this description of orbitals of atom occupied by electrons is known as electronic configuration.

Electrons are distributed in the orbitals the of subshell. The specific region of space in which the movement of electrons are confined is said to be shells which are divided into subshells and are s-, p-, d-, and f-. Among these subshells, the electrons are grouped as orbitals.

The number of electrons that these subshells can hold are:

s-block - 2

p-block - 6

d-block - 10

f-block - 14

The increasing order of energy of shells, subshell is:

As the number of electrons for a neutral atom is equal to the atomic number of an atom. Thus, number of electrons in Al is 13. So, the electronic configuration of Al is:

${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^{\text{1}}$

Since, the preceding noble gas with an atomic number less than aluminum is neon, $\text{Ne}$ so, the noble gas shorthand configuration of Al is:

$\left[\text{Ne}\right]\text{ 3s² 3p¹}$