The Brainliest Answer!
All matter is made up of atoms. In the center of the atom is the nucleus which is a cluster of protons and neutrons, the protons have a positive electric charge while the neutrons are electrically neutral.The nucleus makes up almost all of an atom's mass or weight. Whirling at fantastic speeds around the nucleus are smaller and lighter particles called electrons which have a negative electric charge.  

That's all I know about the structureof an atom. :-)
2 4 2