In a sample of 1000 atoms of an unknown element, it is found that 14 are isotopes of mass 203.973 amu, 241 are isotopes of mass 205.9745, 221
are isotopes of mass 206.9759, and the remaining 524 are isotopes of
mass 207.9766 amu.
1. Calculate the average atomic mass of the unknown substance. Answer
with four decimal places
1. Determine the identity of the unknown element.

c most likely

hop this let me know if it is wrong

  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-

po-215 i got it right on the quiz