Solid phosphorus trichloride is produced by reacting solid phosphorus and chlorine gas.

Question

2P + 3Cl2 -----> 2PCl3

is that right?

Answer 1

yes

Answer 2

Thanks. Can you explain to me when I have to add charges to my the thing? and when I can't?

Answer 3

Atoms are neutral and carry no charge. Ions have a charge.
And I don't know if your professor is using P4 for phosphorus or not. If so, your equation needs adjusting.