Periodic trends in electronegativity and ionisation energy for period 3 elements

Steps:

• Identify element order: Na (group 1), Mg (group 2), Si (group 14) in period 3.
• Recall first ionisation energies: Na (496 kJ/mol) < Mg (738 kJ/mol) < Si (786 kJ/mol), increasing across the period.
• Recall electronegativities (Pauling scale): Na (0.9) < Mg (1.2) < Si (1.8), also increasing due to increasing nuclear charge.
• Correct diagram plots EN rising with IE, matching both trends.

Why B is correct:

• It accurately shows EN increasing linearly with IE from Na to Mg to Si, aligning with the effective nuclear charge trend in the periodic table.

Why the others are wrong:

• A: Places Si with lowest IE, contradicting the increasing IE trend.
• C: Depicts EN decreasing as IE increases, opposite to periodic behavior.
• D: Positions Mg with highest EN, ignoring Si's greater value from higher group number.

Final answer: B