Ionization energy increases across the period in the periodic table because

  • A atomic number increases
  • B effective nuclear charge increases
  • C mass number decreases
  • D screening effect decreases
waec 2022chemistry

The correct answer is B. effective nuclear charge increases

As the nuclear charge increases, its attraction for the outermost electron increases and so more energy is required to remove the outermost electron. Hence, the ionization energy increases.

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