A compound with known empirical formula nh2 has a mass spectrum with a large peak at 32. What is the molecular formula of this substance?.

Cr(oh)3 -> cr(3+) + 3oh-

Ch4 and ph3 are both covalent since they are composed both of non-metals.    ch4 is non- polar because of  london forces and has a geometry of tetrahedral  ph3 , on the other hand, is umbrella shaped polar and has dipole-dipole intermolecular force (imf) . since ph3 is polar, it has a stronger imf   

It would be true sodium reacts with water in a violent way 

In any atom of any element, you will find protons and neutrons in the nucleus of any atom