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.
atom the smallest component of an element. All elements are composed of tiny indivisible particles called atoms. the smallest part of an element that retains its identity in a chemical reaction. atomic theory a theory of the structure of the atom.