Question

Covalent molecules that have central atoms that do not have eight electrons are considered to the octet rule.

a. true
b. false

Answer 1

The statement in the question is false. Covalent molecules that have central atoms that do not have eight electrons are considered exceptions to the octet rule.

Step-by-step explanation:

The statement in the question is false. Covalent molecules that have central atoms that do not have eight electrons are considered exceptions to the octet rule. The octet rule states that atoms tend to gain, lose, or share electrons in order to achieve a full outer shell of eight electrons (except for hydrogen, which needs only two electrons).

These exceptions to the octet rule fall into three categories:

1. Odd-electron molecules: These molecules have an odd number of valence electrons, resulting in an unpaired electron. Examples include NO, NO2, and ClO2.
2. Electron-deficient (diminished octet) molecules: These molecules have a central atom that has fewer electrons than needed for a noble gas configuration. Examples include covalent compounds of beryllium and boron.
3. Expanded octet (hypervalent) molecules: These molecules have a central atom that has more electrons than needed for a noble gas configuration. Examples include PF5 and SF6.