3) How many grams are in each elemental sample? a. 3.01 mol Pt

b. 7.9 mol Rb

c. .248 mol Cu

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 decreases by 4 is your answer mark brainliest