If we heat it enough, any material will become gaseous, then turn into plasma. But we can't do the reverse with some things. No matter how much we cool it, we can never obtain, say, solid helium. We've cooled it down to turning it into a superfluid, but it never turns solid before we hit absolute zero. Why?
-
Something solidifies when there are bonds between adjacent atoms.
When the heat is less than a certain amount the kinetic energy is less than the binding energy and the atoms all join together in some form of lattice.
There are many consequences of this. The energy of fusion is the energy contained in these bonds for example.
But Helium, Neon, Argon, Krypton are all inert gases. They have a full outer shell of electrons and do not bind to other atoms.
So there are no forces to cause them to become a solid. Even in the absence of any thermal kinetic energy.
When the heat is less than a certain amount the kinetic energy is less than the binding energy and the atoms all join together in some form of lattice.
There are many consequences of this. The energy of fusion is the energy contained in these bonds for example.
But Helium, Neon, Argon, Krypton are all inert gases. They have a full outer shell of electrons and do not bind to other atoms.
So there are no forces to cause them to become a solid. Even in the absence of any thermal kinetic energy.
-
Because helium cannot solidify unless it is at absolute zero, it requires all atoms to loose all energy and close the gaps between them, helium only does this at absolute zero.
-
because helium cannot solidify it is absolute zero