EA:
The data adds upto 100%, but there is the mystery element.  However, (fortunately) we are given the MW = 76.526 g/mol so we can establish how much "X" there is.... 46.33 % of 76.526 g/mol = 35.45 g/mol.  This cannot be anything like 2 x O or 2 x N... (if in doubt, check the MW which should be an excellent match.... even a single unit off is WRONG and should be a warning sign.)  A look at a periodic table, maybe focussing on the more common elements would reveal Cl as being a perfect match.
So the empirical formula = C₃H₅Cl.

GEOMETRIC isomers.... (C=C with cis / trans or E / Z isomers) has to be  E-1-chloropropene and Z-1-chloropropene.
CONSTITUTIONAL isomers .... there are 3 other isomers, chlorocyclopropane, 2-chloropropene and 3-chloropropene.
RESONANCE.....Only those structures with p bonds can exhibit resonance, so there can be no resonance in the cyclopropane. However all those with p bonds can exhibit resonance we have a couple of general possibilities that are shown above.  Note that in principle, the lone pairs on the Cl atom could be used to stabilise an adjacent +ve charge.