Are all the elements able to exist in the three states.?

Question

Solid Liquid and Gas.

Answer 1

Theoretically, I would say so. At absolute 0 (0 Kelvin), all motion stops, and every element solidifies at some point while approaching 0 Kelvin. At 0 Kelvin, the matter would actually cease to exist altogether. This would include Nitrogen and Helium, which do not even condense until a very low temperature.

As for liquid, the only thing I can think of that we regularly see in solid and gaseous forms but not liquid would be carbon dioxide. Dry ice usually sublimates directly into CO2 gas, but I would surmise that there is, theoretically at least, a temperature at which it passes from solid to liquid and not yet to gas, though that temperature range is probably to minuscule to reliably be maintained or even measured by human instruments we have available at this time.

As for gas... hmmm. It sounds like such a weird concept that metals could evaporate. Again, though, I would have to say that they probably could at some sort of theoretical extreme, though it would have to be an absurdly high temperature.

Answer 2

The short answer is "yes".

The long answer is also "yes" but it's not that simple.  A few elements require rather extraordinary conditions to achieve liquid state as they sublime directly to the gas (such as carbon), but under high pressure liquid carbon can be formed.

A few of the most unstable elements have never really been isolated.  We have every reason to believe that all three states can exist for them, but we don't know that for a fact.

Answer 3

You'd have to be really specific to answer this, I would say no to your question because some elements (Uuq and what not) are so radioactive they only exist for nanoseconds.  So I doubt you could get enough of them to produce a liquid.  Although maybe you could relativistically.  

I don't know if Helium ever becomes a solid, but it would be very cold and very high pressure.  

The guy below me is way off, carbon dioxide can be a liquid at high pressures, and it's not an element its a compound.  If you include compounds, then a bunch of them can't exist in the gas phase because they burn before they get to that point.  Paper will burn before it turns into a liquid.  Maybe if you heated in a nitrogen environment, but this isn't what your question asks.

And metals can totally become liquids and gases, potassium metal is obtained by adding liquid potassium chloride to liquid sodium to make liquid sodium chloride and liquid potassium.