Which group of elements are the most reactive

The most reactive group of elements are found in group 1 which are alkali metals.

Explanation:

The reason why they are so reactive is because they only electron in the outer shell so this causes the to lose that one electron in ionic bonding with other elements.

the solar system used to have much dust particles option no d

  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-