I need help with a chemistry assignment

I need help with a chemistry assignment.

the correct orbital configuration of carbon is

1s^2 2s^1 2p^3

1s^1 2s^2 2p^3

1s^2 2s^2 2p^4

1s^2 2s^2 2p^2

22 what is the formula for lead (lV) oxide?

PbO2

PbO

Pb2O

Pb2O2

23 what is the name of the compound whose formula is CaSO4

calicium sulfoxide

calcium sulfate

calicum(l) sulfate

calicum sulfur tetroxide

24 which of these is a balanced chemical equation?

CH4+2O2–>CO2+2H2O

CH4+3O2–>CO2+H2O

CH4+O2–>CO2+H2O

CH4+3O2–>CO2+2H2O