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

What is a covalent bond?

1. Weak attraction between ionic charges

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

3. Non-bonding interaction of electrons

4. Partial charge interaction between molecules

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

A covalent bond is defined as a strong attraction that occurs when two atoms share a pair of electrons. This sharing allows each atom to attain a more stable electron configuration, typically achieving a full outer shell akin to the noble gases. In a covalent bond, the shared electrons are attracted to the positively charged nuclei of both atoms. This results in a stable linkage between the atoms, as the mutual attraction helps hold them together, creating a molecule. This description captures the fundamental nature of covalent bonding, distinguishing it from other types of chemical bonding, such as ionic bonding, where one atom transfers electrons to another rather than sharing them. This is why the other options do not accurately define a covalent bond, with choices focusing on different types of interactions that do not involve electron sharing, such as weak attractions or non-bonding interactions.