It called when water molecules change from liquid to gas

- "the choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."

a:

by the combination of an unlimited number of elements

it's all four options.

a electronegativity decreases beacuse the size of nucleus is bigger.