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.
Atomic mass is roughly equal to the sum of the individual particle masses of an atom. Atoms have three basic components: protons (positively charged particles), neutrons (non-charged particles), and electrons (negatively charged particles).