'Silicon and phosphorus are both covalent substances, but silicon has a much higher melting temperature than phosphorus' Explain this statement. That was the question..im a bit stuck on it. I dont usually ask here, but im out of ideas for this for now.. I first thought of the electronic configuration of the two elements, with Si having 2p2 and P having 2p3. I first thought the number of molecular orbitals might be larger for Phosphurous, but found out the question was asking the reason for the opposite! doh! If you need more detail for my effort put into this question, ill gladly post.. however, i need some help with this question. Thanks in advance to those who help. EDIT: i think it has to do something with the shape and structure of the molecules the atoms form when they covelently bond with other atoms. Im off to research, but thanks to anyone who helps..