Sleep Number King Size 2-3 inch Mattress Bed Foam Topper Pad 7000, i8, i9.
Quick Answer. The three parts of an atom are the protons, neutrons and electrons. Atoms make up the basic building blocks of matter and define the structure of elements. These parts were not officially identified until 1932.
General Chemistry/Atoms and Molecules - Atoms. 1  An atom is the smallest unit of matter that has the properties of an element. 2  The nucleus, composed of protons and neutrons, is at the center of an atom. 3  The electron has an electric charge equal but opposite the proton (that is, they cancel).