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Explaining Trends in Group 1

Increasing Reactivity

  • As you go down group 1, the more shells an atom has, the further the outer shell electron is from the nucleus
  • This decreases the attraction between the nucleus and the outer shell electron
  • This makes it easier to remove the outer shell electron and so the more reactive the alkali metal is

  • The electrons blocking the outer shell electron is called electron shielding
    • They block the nucleus' attraction by repelling the outer shell electron (negative -> negative = repel)