Water vapor is the way to describe which form of water?

Water vapor is water in its gaseous state-instead of liquid or solid (ice). Water vapor is totally invisible. If you see a cloud, fog, or mist, these are all liquid water, not water vapor. Water vapor is extremely important to the weather and climate.

Explanation:

the water form is when the water is too hot that's when the vapor starts to come out

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.