1. The problem statement, all variables and given/known data http://i.imgur.com/8pFdEDX.png 2. Relevant equations polarity of the element 3. The attempt at a solution BCl3 is a trigonal planar which the forces would be balanced. Thus it is a neutral substance. XeF4 is with tetrahedral shape where one side is a lone pair, which the charge is imbalanced and it has dipole dipole attraction between molecules. However, I don't know the other two - AsH3 and SCl3, which one is with dipole dipole attraction between molecules? And why? Thank you very much!