Metallic Element

[guhorwine]

What is the only metallic element that can be solid, liquid or gas?

[Nibble]

Mercury

[alanogden]

Mercury is liquid and gas at normal temperatures and can be solidified with cooling.

[beso]

Many metals can be solid liquid or gas. It depends on the temperature.

[Bert]

Mercury is the only metallic element that is a liquid at "normal" temperatures. As all liquids have a vapour pressure, there will also be mercury vapour at normal temperatures. Mercury freezes at about -39ºC, so it would not work in a thermometer in Arctic or Antarctic conditions. Bromine is the only other element that is liquid at "normal" temperatures. It freezes at -7.2ºC.
But, given the right temperature and pressure, and the absence of other elements or compounds that might react, all the elements, metallic or not, can be solid, liquid, or gas.

[beso]

We were taught at school that there were three states of matter, solid, liquid and gas.

In fact there a many more but one does not have to go to QuarkSoup or Bose-Einstein condensate to see them.

A very common form of matter where the elements is still itself is the Plasma and it aught to be included in the common states of matter taught to children.

[chakka35]

Depending how warm day it is, there are other metals that can be liquid at room temperature. Caesium (melting point 28C), Francium (27C) and Gallium (30C). It's stretching it a bit to include Rubidium (39C).

[ToraToraTora]

all of them.