A Level Chemistry OCR Practice Exam

What is the main characteristic of a dative covalent bond?

1. It involves the complete transfer of electrons

2. It involves the shared donation of both electrons from one atom

3. It forms only in ionic compounds

4. It creates a stronger bond than a regular covalent bond

The correct answer is: It involves the shared donation of both electrons from one atom

A dative covalent bond, also known as a coordinate bond, is characterized by one atom providing both of the electrons that are shared in the bond. In this type of bond, one atom has a lone pair of electrons that it donates to another atom, which does not contribute any electrons to the bond. This unique formation distinguishes dative bonds from regular covalent bonds, where each atom typically contributes one electron to the bond. The nature of this bond allows for the formation of complex ions and coordination compounds, often seen in transition metal chemistry. This type of bonding plays a crucial role in various chemical reactions and molecular structures, particularly in the context of Lewis acids and bases. In contrast, the other options do not accurately describe a dative covalent bond. The notion of complete transfer of electrons pertains more to ionic bonding, and claiming dative bonds are exclusive to ionic compounds misrepresents the nature of this bonding type, as they can exist in molecular compounds as well. The strength of a dative covalent bond relative to a regular covalent bond is context-dependent and cannot be generalized as stronger or weaker universally. Thus, the defining characteristic remains the donation and sharing of both electrons by one atom.