A solid with a low melting point is most likely is held together by covalent bonds. Examples are hydrocarbons, ice, sugar and sulfur. The have low melting points because of the covalent bonds . It do not form crystals therefore can easily be broken. The attractions are weak.
Answer: option C. the number of electrons in the atom.
Given that the charge of a proton is the same that the charge of an electron, to be neutral the number of protons has to be the same than the number of electrons.
Energy helps the moving precess
