Answer:
each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.
Explanation:
There will be 89.865 grams of Ar. If you put it in sig figs, it will be rounded to 89.9g At.
I don't know because I'm in 5th grade but I will try
no because the temperature is changing from cold to hot to hotter hope I helped
