Headings Halogens Search Questions 
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The Halogens - Group Trends.
As you go down group 7 from fluorine to astatine, they
1) Have bigger atoms.
Each successive element has an extra electron shell.
It is the electron shells which take
up nearly all the
space of an atom.
2) Are less reactive. Fluorine is the most
reactive, astatine the least.
As the size of the atoms increase, the
extra outer electron
(which it
wants to gain or share to become a stable ion or
molecule)
is further and further from the positive nucleus.
It is the attraction between the negative incoming electron
and the
positive nucleus
which determines how easily the
electron will be gained.
The smaller the atom, the closer the
incoming outer electron is,
the more easily it is gained,
and the more reactive the halogen
is.
Also, the smaller the atom, the less
shielding there
is.
3) Have higher melting and boiling points because the atoms are heavier.
Headings Halogens Search Questions
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