Identify the parts of the atom that are labeled in the
diagram.
label a:
label b:

A - nucleus.

B- electron cloud.

Explanation:

Atom is the small part of the element that contains the sub atomic particles. The sub atomic particles of the atom are the protons, electrons and the neutrons.

Nucleus is present in the center of the atom and contains the proton and neutron. The picture in the label A shows the nucleus. Electrons has the ability to revolve around the nucleus in a fixed circular orbit. Electron cloud represents the spreading of the electrons energy.

Thus, the answer is A - nucleus.

B- electron cloud.