A Level Biology Practice Exam

What characterizes an ionic bond?

1. Sharing of electrons between atoms

2. Formation of covalent compounds

3. Donation of an electron from one atom to another

4. Combination of two non-metals

The correct answer is: Donation of an electron from one atom to another

The characteristic of an ionic bond is indeed the donation of an electron from one atom to another. In ionic bonding, one atom, typically a metal, donates one or more of its electrons to another atom, usually a non-metal. This transfer of electrons leads to the formation of positively charged ions (cations) and negatively charged ions (anions). The resulting electrostatic attraction between these oppositely charged ions forms the ionic bond. In contrast, sharing of electrons describes a covalent bond, where atoms hold onto their electrons in a shared manner to achieve stability. The formation of covalent compounds specifically arises from such bonding between non-metals, which does not pertain to ionic bonding. Additionally, the combination of two non-metals typically results in covalent bonding rather than ionic bonding. Thus, the correct identification of an ionic bond by focusing on the electron donation is crucial to understanding the nature of such interactions.