text: Just about everything in chemistry has to do with the outer valence shell.  This is no exception.\n\nThe metals in this row (period 6) basically bond with each other using their s and d orbitals.  As with everything else, this works best when you have 1 electron in each (e.g. H2) and worst when they're already full (e.g. He2).  Mercury has them all (it's in column 12 = 2s + 10d), and therefore VERY poor bonding.  In constrast, tungsten (W) has half of them, and exceptional bonding (MP-3422 C), which is why it's used as the filament in light bulbs.\n\nSo why are Cd and Zn solids if they're the same column as Hg?  It has to do mostly with the size (larger = further = weaker bonding), but is best described using band theory.  I'd recommend looking there.  \n\nP.S. Things wierd when there are this many electrons in one atom, like yellow gold.