atomic number and mass number of elements

compounds: atoms of 2+ elements chemically bonded

ionic bonding
transferring electrons to form charged particles (ions)
atoms need full outer shell

ions: atoms lost or gained electron(s)
electronic structure of noble gas

positive ions
group 1: +1
group 2: +2

sodium chloride
ions

covalent bonding
sharing electrons
fill outer shell

simple molecular substances
very strong covalent bonds to form small molecules of several atoms

giant covalent structures
lattices: no charged ions
strong covalent bonds

diamond
4 covalent bonds
very rigid and hard

graphite
3 covalent bonds
slide over each other
weak intermolecular forces

metallic structures
sea of free electrons
conduct heat/electricity
electrostatic attraction: positive metal ions and negative electrons

polymers
thermosoftening: weak intermolecular forces - no crosslinks - free slide over
thermosetting: strong intermolecular forces - crosslinks - solid structure

relative formula mass
atomic mass

reacting mass calculations
moles = mass divided by relative formula mass

balancing equations

catalysts:
chemical that speeds up a reaction without being used up

rate of reaction

combining powers and charges of compounds

measuring rates of reaction

collision theory
how often the reacting particles collide successfully

exothermic reaction: transfers energy to surroundings - heat
e.g combustion, oxidation

reversible reactions

acids and alkalis
neutralise
acids: H+ ions
alkali: OH- ions

acid + base > salt + water

symbols for physical state

acids reacting with metals
acid + metal > salt + hydrogen

oxides, hydroxides and ammonia

making salts