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 - (physics and chemistry) the smallest component of an element having the chemical properties of the element. substance - the real physical matter of which a person or thing consists; DNA is the substance of our genes.