Do S and Na have the same number of
electron shelis?

Yes

Explanation:

Sulfur and Sodium will have the same number of electron shells.

  Electronic configuration of

           k   l  m

  Na = 2  8  1

   S =  2  8  6

We see that the have the same energy level.

Also, they belong to the same period on the periodic table. Elements in the same period will have equal number of shell.

fe 55.85 g/mol and h2o 18.02 g/mol.