Protons, neutrons, and electrons in atoms | Chemistry | Khan Academy

Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now! Want to explore more? Check out the full Atoms, isotopes, and ions playlist here: Atoms are made up of three types of subatomic particles: protons, neutrons, and electrons. Protons and neutrons are found in the nucleus, the dense region at the center of an atom. Electrons are found outside the nucleus. Protons are positively charged and have a mass of about 1 u. Neutrons are neutral (have no charge) and also have a mass of about 1 u. Electrons are negatively charged and have a much smaller mass of about 0.0005 u. Sections: 00:00 - Introduction to atoms 00:19 - Atoms as building blocks of matter 00:40 - Structure of the…