Which statement describes the electronegativity trend across the periodic table?

• A. Increases across a period
• B. Decreases down a group and increases across a period
• C. Increases down a group and increases across a period
• D. Decreases down a group and increases across a period

Answer: (D)

Electronegativity describes an atom’s ability to attract bonding electrons. As you move from left to right across a period, the number of protons increases while the added electrons enter the same energy level, so the effective nuclear charge felt by the valence electrons rises. This stronger pull makes atoms more capable of attracting electrons in a bond, so electronegativity increases across the period. Moving down a group, atoms gain shells and shielding increases, pushing valence electrons farther from the nucleus. The greater distance and shielding weaken the nucleus’s pull on shared electrons, reducing electronegativity. Therefore, electronegativity decreases down a group and increases across a period.