can you please tell me if I have the correct molecule type

PO4 3- polar

SO3 polar

NO2- polar

BrCl polar

2 answers

phosphate tetrahedral in shape; therefore is non-polar.
SO3 is trigonal planar which makes it non-polar.(see http://www.tutor-homework.com/Chemistry_Help/Molecular_Geometry/049_Sulfur_Trioxide_SO3.html)
NO2- is trigonal planar electronic geometry but molecular geometry is bent or v-shaped which makes it polar.
BrCl is polar because although linear there is a light difference in electronegativity between Br and Cl.
calculate number of molecules in carbon atom