How does fluorine (f) differ from iodine (i)?

Explanation:

Both fluorine and iodine are non-metals. As it is known that when we move down the group there will be decrease in reactivity.

Hence, reactivity of fluorine is much more than the reactivity of iodine.

Also, fluorine is smaller in size as compared to iodine atom due to this nucleus of fluorine is able to strongly pull the electrons more towards itself.

Whereas nucleus of iodine atom is shielded by electron shells due to which it is not able to strongly pull the electrons from a donor atom.  

Also, fluorine is present in gaseous state at room temperature and iodine exists as a solid at room temperature.

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

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