Final answer:
The most electronegative atom among those listed is Oxygen (O).
Step-by-step explanation:
The most electronegative atom among those listed is Oxygen (O).
Electronegativity is a measure of an atom's ability to attract electrons towards itself in a chemical bond. Oxygen is highly electronegative because it has a higher tendency to attract electrons due to its high effective nuclear charge and smaller atomic size.
For example, in water (H2O), the oxygen atom attracts the shared electrons more strongly than the hydrogen atoms, resulting in a partial negative charge near the oxygen atom and partial positive charges near the hydrogen atoms.