An atom has a small, positively charged nucleus surrounded by a large region in which scientists can predict where an electron is likely to be

Wave model

Explanation:

An atom has a small, positively charged nucleus surrounded by a large region in which scientists can predict where an electron is likely to be found wave model.

b

explanation:

mitosis

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons