What takes up the vast majority of space in an atom? a relatively small nucleus, a relatively large nucleus, a relatively large electron cloud, a relatively small electron cloud

The answer is: a relatively large electron cloud.

Atom is composed of the nucleus and the electron cloud.

Protons (positive particles) and neutrons (neutral particles) are in the nucleus of an atom and electrons (negative particles) are in the electron cloud.

Nucleus is in the centar of the atom atom and electron cloud is surrounding it.

Atoms have their mass concentrated in a very small nucleus.