Question

the region around the nucleus that takes of the most volume of the atom
atomic number
mass number
compound
electron cloud

Explanation:

The electron cloud is the region around the nucleus where electrons are likely to be found. It takes up most of the volume of an atom. The atomic number is the number of protons in the nucleus, the mass - number is the sum of protons and neutrons in the nucleus, and a compound is a substance made up of two or more different types of atoms chemically bonded together.

Answer:

Electron Cloud