Chapter 7.5, Problem 4CP

Interpretation Introduction

Interpretation:

The correct ground state electron configuration for ${\text{S}}^{2-}$ is to be identified.

Concept Introduction:

General rules for writing electron configuration are asfollows:

Electrons will reside in the available orbitals of lowest possible energy.

Each orbital can accommodate a maximum of two electrons.

Electrons will not pair in degenerate orbitals if an empty orbital is available.

Orbitals will fill in order of increasing energy $1s2s2p3s3p4s3d4p5s4d5p6s4f$

s-orbital can have 0–2 electrons

p-orbital can have 0–6 electrons

d-orbital can have 0–10 electrons

f-orbital can have 0–14 electrons

In electron configuration, noble gas symbol in brackets represents core electrons.

The number of electrons in a neutral atom is equal to its atomic number.

In ions, the number of electrons is not equal to the atomic number of that atom.

It may be lesser or greater than the atomic number.

A cation contains less number of electrons than the atomic number of the atom.

Anions contain more number of electrons than theatomic number of the atom.