Question

which part of an atom is mostly empty space?
o nucleus
o proton cloud
o electron cloud
o neutron

Explanation:

The electron cloud is the region around the nucleus where electrons are likely to be found. It has a large volume relative to the size of the electrons within it, making it mostly empty space. The nucleus is dense with protons and neutrons, and there is no such thing as a "proton cloud" in the context of atomic structure. Neutrons are sub - atomic particles within the nucleus.

Answer:

C. electron cloud