Find the molecular formula of elements X and Y. X = 88 Y = 35. Explain how please.

Question

I know that the answer is XY2 but I cannot figure out how. I subtract 80 by 60 to get 28 then by 32 to get 4 electrons for Element X but i'm not sure if that is correct.

 

Answer 1

According to aufbau rule the electrons in each shell

 X=88 (2, 8, 18, 32, 18, 8, 2 )

Y=35 (2, 8, 18, 7)

 

in outer shell there are two electrons in X(which can be unpaired as s and p shells are of nearly same energy levels ) and 7 electrons in Y (where only one is unpaired)

So make an element we need two atoms of Y as their one unpaired electron of each Y will shares the electrons in the  bond with the unpaired electrons of one unpaired electrons of x.