The atomic radius generally decreases from left to right across a period because

Options

  • A. Number of shells decreases
  • B. Effective nuclear charge increases
  • C. Number of neutrons becomes zero
  • D. Atomic mass always decreases
  • E. None of the above

Correct Answer (Detailed Explanation is Below)

B. Effective nuclear charge increases

Detailed Explanation

Across a period, electrons are added to the same principal shell while nuclear charge increases, producing greater effective nuclear attraction and a smaller atomic radius.