This image depicts the radium atom’s pear-shaped nucleus of protons and neutrons in the center, surrounded by a cloud of electrons (yellow), and an electron (yellow ball with arrow) that has a ...

Part of Physics (Single Science) Unit 1: Atomic and nuclear physics Most of the mass and all of the positive charge of an atom is in the nucleus. Most of an atom is empty space, (a vacuum). In 1897, ...

Atoms are the building blocks of matter. Everything around us — from air and water, to rocks, plants and animals — as well as everything within our bodies, is made up of atoms. They are very small, ...