group 7

• Group 7 elements

  • When a group 7 element takes part in a reaction, its atoms each gain one electron
  • The atoms form negatively charged ions
  • The ions have a stable arrangement of electrons, with a complete outer shell
• Going down group 7

  • The atoms become larger
  • The outer shell becomes further from the nucleus
  • The force of attraction between the nucleus and the outer shell decreases
  • An outer electron is gained less easily
  • The halogen becomes less reactive