Chemistry UNIT 1.2

• Helium nuclei is alpha radiation
• Fast moving electrons is beta radiation
• Gamma rays are high energy waves
• Alpha decay emits a helium nucleus
• Beta decay emits a high energy electron when a neutron changes to a proton
• Electron capture occurs when an orbiting electron is captured by a proton to form a neutron
• Positron emission is when a proton is converted into a neutron
• Half-life is the time taken for half the atoms in a radioisotope to fall to half it's initial value
• Medicine has radiotherapy and medical tracers
• Radio-dating can find out the age of a plant and animal remains
• Analysis is the mass of a substance in a mixture
• Sub-shells are s,p,d and f
• All sub-shells have orbitals
• 4S sub-shell always gets filled up before 3D
• Orbitals are regions where electrons are most likely to be found
• The first shell contains two orbitals (one p and one s)