What is radioactivity? what is radioactivity? radioactivity is spontaneous radiation from an atomic nucleus. radioactivity is controlled radiation from a atomic nucleus. radioactivity is controlled radiation from a molecule. radioactivity is spontaneous radiation from a molecule?

120,630,890

step-by-step explanation:

110+10=120,620+10=630,880+10=890

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.