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.
In the next sub-unit you will learn about the the outer shell of an atom called the valence shell. Review. Atoms have their electrons arranged in layers called shells. In order to maintain electrical balance the number of electrons is equal to the number of protons in most elements.