Saturday, April 30, 2011

Chemistry Form 4: Chapter 4 - Reactivity of Group 17

  • When a halogen atom reacts, it gains an electron to form a singly charged negative ion which has a stable noble gas electron arrangement.
  • As you go down the group of 17, the atomic radius gets bigger due to an extra filled electron shell. 
  • The valence electron is further and further away from the nucleus.
  • The forces of attraction between the nucleus and the valence electrons become weaker, making it more difficult to gain electrons.
  • Therefore, the halogen is less reactive down the group.

No comments: