Humber Admissions Practice Test

What defines electronegativity?

1. The ability of an atom to share electrons

2. The ability of an atom to attract electrons in a bond

3. The measure of atomic mass

4. The number of protons in an atom

The correct answer is: The ability of an atom to attract electrons in a bond

Electronegativity is defined specifically as the ability of an atom to attract electrons in a chemical bond. This concept is vital in understanding how atoms interact with each other during the formation of molecules. The strength of an atom's electronegativity influences the distribution of electron density between bonded atoms, which can affect molecular geometry, bond polarity, and reactivity. For instance, in a covalent bond where two different atoms are involved, the atom with higher electronegativity will attract the shared electrons more strongly, leading to a polar bond. While other options present concepts related to atomic structure and interactions, they do not encapsulate the specific nature of electronegativity. Sharing electrons, for example, relates to covalent bonding but does not define the competitive aspect of attracting electrons. Atomic mass and the number of protons pertain to an atom's identity and weight rather than its ability to attract electrons. Thus, the correct choice clearly distinguishes the role of electronegativity in chemical bonding.