The trend for ionization energy across a period in the periodic table

The trend for ionization energy across a period in the periodic table

  1. Increases from left to right. ✓
  2. Decreases from left to right.
  3. Remains constant.
  4. Varies randomly.

Explanation

Ionization energy increases left to right across periods. More protons pull electrons tighter. Removing electrons becomes harder.

Moving down groups decreases ionization energy. Electrons sit farther from nucleus. They’re easier to remove.

Remember: Noble gases have highest ionization energy. Alkali metals have lowest.