Electronegativity trend in period 3 Steps:

• Recall period 3 elements (Na to Cl) show increasing effective nuclear charge across the period.
• Electronegativity measures atom's pull on electrons and rises from metals to non-metals.
• Identify graph with steady increase in y-values from left (Na) to right (Cl).
• Match to option D, which shows this monotonic rise.

Why D is correct:

• Electronegativity follows Pauling scale, increasing due to higher nuclear charge and smaller atomic size, from 0.9 (Na) to 3.0 (Cl).

Why the others are wrong:

• A shows decreasing trend, matching atomic radius decrease.
• B shows irregular peaks, matching melting point variations.
• C shows general increase with dips, matching first ionization energy.

Final answer: D