Structural Formulas for Covalent Molecules

Is anyone good at doing these because I am so confused




1) C2H4





2) C3Cl8





3) SCl2





4) HClO2





5) HNO2





6) H2SeO3





7) H2S2





8) C2H6O2



9) C2H7N





10) C2NH3





11) C2PSH3





12) CH2O2PN





13) C2H2S





14) CH2O





15) N2H2