International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

What is a key characteristic of covalent bonds when comparing them to ionic bonds?

1. Covalent bonds involve the donation of electrons

2. Covalent bonds are generally weaker than ionic bonds

3. Covalent bonds involve sharing of electrons

4. Covalent bonds do not form molecules

The correct answer is: Covalent bonds involve sharing of electrons

Covalent bonds are defined by the sharing of electrons between atoms. This characteristic distinguishes them significantly from ionic bonds, where electrons are transferred from one atom to another, leading to the formation of charged ions. In covalent bonding, atoms achieve stability by sharing one or more pairs of electrons, which allows them to fill their outer electron shells and attain a noble gas configuration. In molecular compounds formed by covalent bonds, the shared electrons create a strong attractive force that holds the atoms together, typically resulting in the formation of distinct molecules. This is a fundamental concept in chemistry, as it leads to the diverse array of molecular structures and properties observed in covalently bonded substances. Understanding this characteristic is crucial for grasping the differences in chemical bonding and molecular formation compared to ionic compounds, which do not involve electron sharing but rather the electrostatic attraction between oppositely charged ions.