Chapter 3, Problem 3.39AP

Interpretation Introduction

Interpretation: The reason for $\text{H}$ and $\text{He}$ do not obey the octet rule to be explained.

Concept Introduction:

Electron configuration: The distribution of electrons of an atom or molecule in atomic or molecular orbitals.

Octet Rule: The tendency of atoms prefers highly to have eight electrons in their outermost valence shell. In case of atom having fewer electron count less than eight, tend to react and form stable compound by gaining electrons. In case of atom having more than eight electrons tend to react and form stable compound by donating electrons.

Formation of ions: 

Atom possesses equal number of protons and electrons and remains electrically neutral. By gaining (accepting electrons) or losing (donating electrons) one or more electrons, converts the neutral atom into a charged particle called IONS.

Cation: The loss of one or more electrons by a neutral atom leaves the atom positively charged called cation.

Anion: The gain of one or more electrons by a neutral atom leaves the neutral atom negatively charged called anion.

The symbolic representation of ions:

The electrons are reside in the principal quantum number ‘n’; by losing and gaining electron, reduces and increases in the electron count in the electronic configuration of the atom; for a cation adding positive charge as a superscript to the symbol of the element and for the anion adding negative charge as superscript to the symbol of the element.