Atoms, nuclei and radiation

Need to know

What you need to know

• 11.1 Atoms, nuclei and radiation.
• α-particle scattering provided the proof of the structure of the atom.
• When α-particles are fired at thin gold foil, most of them go straight through but a small number bounce straight back.
• Atoms of all elements are made up of three types of particles: protons, neutrons, and electrons.
• The proton number (Z) is the number of protons in an atom, defining the element.
• Almost all the mass of an atom is concentrated in the nucleus, which is held together by the strong nuclear force.

Explanation

Atoms, nuclei and radiation

1. 11.1 Atoms, nuclei and radiation.
2. α-particle scattering provided the proof of the structure of the atom.
3. When α-particles are fired at thin gold foil, most of them go straight through but a small number bounce straight back.
4. Atoms of all elements are made up of three types of particles: protons, neutrons, and electrons.