M4 The
Periodic Table: Halogens
Slide 34 of 45
Halogen Trends in Reactivity
Going down Group 7
Bigger
atoms
one extra full shell of
electrons for each period you go down
Less Reactive
Harder
to gain last electron needed as nucleus is farther away from the valence
shell
In other words when the
following reaction take place
Cl2
(aq) + 2Y-(aq) ฎ 2Cl-(aq) + Y2 (aq) Where Y- = Br- or I-
Chlorine
is able to gain the electrons from bromide and iodide ion more readily because
they dont hold the electrons as strongly as if chlorine were holding it in
its valence shell.
In other words
Br2 (aq) + Cl-(aq) ฎ No reaction
Because
chlorine is able to hold the electron more strongly than bromine would
hold it.
