This guy yesterday was explaining how those elements with....heh....I'll have to go studying, but basically the metals lock together because it is the (you know all this!  I say it so see if I've learnt) metals are willing to share their electrons (hence they conduct electricity)--hence they are solid--locked together.  The noble gasses have perfect outer shells, have no need to bond with anything and so never become solid.  Liquids have strange pairings and water is the strangest of all...I didn't quite get it, but the oxygen can easily transfer its electron (or pick one up) from different hydrogen atoms so there's slippage--liquid.  You and I are mostly made of water so you're not a gaseous ghost--you have spare electrons which are out and about being chucked or hoovered up; but you're not super solid--you're not locked down like rock.  You're fluid, mostly, and so fluidity...

...and yeah, all that empty space!  But we're so huge and the empty space is inside the structures...anyways, I'm gonnae read up on the electron shells...it's a way to learn the names and characteristics of some elements I know nothing about....and I'm sure you're glad I told you that!  

Don't fight forces, use them R. Buckminster Fuller.