A Level Chemistry OCR Practice Exam

Electronegativity measures the ability of an atom to attract the shared pair of electrons in a covalent bond. In a covalent bond, atoms share electrons, but the shared electrons may not be distributed equally, especially when the atoms involved have different electronegativities. The atom with higher electronegativity has a stronger pull on the shared electrons, leading to partial charges and influencing molecular polarity.

This concept is fundamental in understanding chemical bonding and molecular interactions, as it helps predict the behavior of molecules in different chemical environments. The other choices do not accurately reflect the concept of electronegativity; for example, the distance between atoms pertains to bond length, the energy needed to break a bond relates to bond strength, and the total number of electrons in an atom refers to its electronic configuration, not its ability to attract electrons in a bond.