An element is always trying to have 8 valence electrons. Each element must obtain a different number to come to a total of 8
The answer is caso4 and ca(C2H3O2)2
I think you meant 
If you want to do that then you it will be 308
,
000
,
000
or if you meant 3 x 108 then it would literally just be 3 multiplied by 108 = 324
It would weigh 6.77 kilo i believe