Chapter U1.24, Problem 2E

Interpretation Introduction

Interpretation:

The term electronic configuration should be explained.

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.

Answer to Problem 2E

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.

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 of the 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 $\text{s-, p-, d-, and f-}$. 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:

For example:

Writing the electronic configuration of lithium, $\text{Li}$ :

As the number of electrons for a neutral atom is equal to the atomic number of an atom. Thus,

Number of electrons in $\text{Li}$ is 3. So, the electronic configuration of $\text{Li}$ is:

${\text{1s}}^{\text{2}}{\text{2s}}^{\text{1}}$