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

What is the main feature of a covalent bond?

1. Weak forces between molecules

2. Strong attraction between a shared pair of electrons and nuclei

3. Electrostatic attraction between opposite charges

4. Formation of metallic bonds

The correct answer is: Strong attraction between a shared pair of electrons and nuclei

A covalent bond primarily features a strong attraction between a shared pair of electrons and the nuclei of the bonded atoms. In a covalent bond, atoms share electrons to achieve a more stable electronic configuration, often resembling that of noble gases. This sharing of electrons allows each atom involved in the bond to gain a degree of stability because the shared electrons are attracted by the positively charged nuclei of both atoms. This mutual attraction holds the atoms together, resulting in a strong bond. Understanding these fundamental interactions helps explain why covalent compounds typically have distinct properties, such as lower conductivity compared to ionic compounds, and the ability to exist in various states like gases, liquids, or solids. The other options do not characterize covalent bonds. For instance, options concerning weak forces and metallic bonds relate to different types of bonding or intermolecular forces in substances.