posted by Rebekah .
Of each pair of solids, which one has the higher melting point?
a) HCl and KCl
b) Cu and Kr.
Can you please explain? How do you know the melting point? Is it the type of intermolecular force that they have?
There are a number of things to look at. For a, HCl is largely a covalent bond (although polar covalent) while KCl is an ionic solid. Ionic solids melt higher than most covalently bonded materials because the ionic solids must break the crystal lattice bonds. Cu has metallic bonding and Kr has only dispersion forces.