- Current model of atom consists of protons neutrons and electrons - Rows of elements are periods
- Columns of elements (families) are group
- Periodic Law is a recurring pattern with elements
- Mass Number is the number of protons and neutrons in an atom - Atomic Number is the number of protons.
- Alkali Metals are Group I
- Alkaline Earth is Group II
- Halogens are Group VII
- Group VIII are the noble gases.
- Metalloids - Properties of both metals and non-metals.
Patterns in the Periodic Table
Atomic/Mass number increases as you go down a group and increase as you go across a period. Melting points decrease for Groups I-V and increase for groups V-VIII and the opposite as you go across a period Metallic character generally increases as you go down a group and decreases as you go across the period. Isotopes are different atoms of the same element.
Radioisotopes - isotopes that are unstable disintegrate to form other elements.
Nuclear Radiation - Alpha radiation, beta radiation and gamma rays. Alpha Particles - 2 protons and neutrons, positively charged, cannot travel easily. Beta Particles - same size/mass as electrons, both charges and travel at super speed. Half-Life - time taken for half of the nuclei in a sample of a radioisotope to decay. Radio-carbon dating - Testing how much of a radioisotope remains, knowing its half-life, the age can be determined. Nuclear radiation can damage living cells, too much exposure leads to leukaemia. Nuclear Reactors - Electricity generators that use uranium. Process - Converted to uranium dioxide then sealed in rods, called fuel rods, before undergoing a fission reaction.
Molecules - Two or more atoms that join together.
Compounds - Different atoms that join together
Electrons account for the chemical behaviour of all matter.
Electron Shell Diagram - simplified model of an atom.
Shells - Energy levels containing electrons which surround the nucleus. the nth shell holds a maximum of 2n^2...