Chapter 4.2, Problem 2QQ

Interpretation Introduction

Interpretation:

Identification of the number of valence electrons present in an atom with the electron configuration ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^{\text{5}}$.

Concept Introduction:

The electrons present in the outermost shell of the atom are known as valence electrons.

Valence electrons are important because:

• The valence electrons decide the reactivity of an element.
• The valence electrons decide the way an atom forms a bond with another atom.
• The valence electron in an atom decides the combining capacity of the element.
• Except inner transition elements valence electrons are present in s or p subshells of elements.
• For inner transition elements incompletely filled d or f subshells electrons are considered as valence electrons.