Atoms and Molecules

Did you know that an atom is the smallest thing in the world? I'm going to tell you some parts of atoms.

The core is called a nucleus.
And the nucleus is made up of protons and neutrons.

Protons have a positive electrical charge. Electrons move around the nucleus in electron clouds or energy levels, each of which can hold a certain number of electrons. Neutrons have no charge.

Scientists used to think that electrons orbit around the nucleus like the planets orbit around the sun. But they were wrong.