By smallest number of electrons means that solid simple molecular compounds have low melting and boiling points H He -259 -270 '253 -269 gas 2 gas Li Be B C IM O F Ne 180 1280 2030 3500 -210 -219 -220 -249 1340 2500 3700 3900 -196 -183 -188 -246 solid solid solid solid solid gas gas Na 6 M S§ Al Si P S Cl Ar 98 660 1410 44 119 -101 -189 883 1110 2400 2500 280 445 -34 -186 solid solid gas gas K 63 Ca 850 4 3 5 symbol 760 1440 Key m.pt. (°C) solid solid solid solid.