MDCAT Chemistry MCQ #978

What is the primary reason for the decrease in atomic radius across Period 3 (Na to Cl)?

MDCAT Chemistry MCQ #978

  1. Question 1

    Q1. What is the primary reason for the decrease in atomic radius across Period 3 (Na to Cl)?

    • A) Increased effective nuclear charge
    • B) Greater electron shielding
    • C) More subshells being filled
    • D) Stronger electron repulsion

    Answer: Increased effective nuclear charge

    Explanation: Effective nuclear charge increases across period, pulling electrons closer. Shielding (B) increases less rapidly.