Chapter 8.3, Problem 52SSC

Interpretation Introduction

Interpretation:

The phrases valence electrons, expanded octet, less than octet needs to be matched with the molecules ${\text{PCl}}_{\text{5}}\text{,}{\text{ClO}}_{\text{2}}\text{,}{\text{BH}}_{\text{3}}$.

Concept introduction:

Atoms tend to gain, loss, or share electrons until they are compete the octet or have 8 electrons in the outermost shell. This rule is termed as octet rule.

Answer to Problem 52SSC

The compound which is less than octet is ${\text{BH}}_{\text{3}}$. Compound that has less number of valence electron is ${\text{ClO}}_{\text{2}}$ and ${\text{PCl}}_{\text{5}}$ has d sub shell or energy level that is expanded octet.

Explanation of Solution

${\text{BH}}_{\text{3}}$ is less than octet. The number of electron in B is 3 and it shares with 3 H atom thus, total number of electron is 6 that is less than an octet. ${\text{ClO}}_{\text{2}}$ has odd number of valence electrons. Chlorine has 7 electrons and oxygen has 6 electrons. Thus total number of electrons involved is 19, it is an odd number. ${\text{PCl}}_{\text{5}}$ is a nonmetallic compound that has P central atom. P is belongs to 3^rd period. There are d orbital in 3^rd energy level. Here, number of valence electrons in P is 3 so it can combine with 3 Cl atoms but here 5 Cl atoms are present because P extends its octet.