Chemistry unit 1

Question	Answer
Isotopes	Have the same number of electrons and protons as but they have a different number of neutrons. Example: C-11 C-12 C13 they all have 6 protons but C-11 has 5 neutrons, C-12 has 6 neutrons and C-13 has 7 neutrons.
Shapes of molecules	Electron pairs repel. Molecules have different shapes when there are different numbers of bonded electron pairs. The shapes
Shapes of Molecules: II	Trigonal planar Tetrahedral Octahedral
Empirical formulae	Simplist way to show formula. To calculate: find the molar ratio of atoms (divide the mass by the RFM), divide by smallest number, then use ratio to work out formula.
Ions formulae	Has an overall charge of zero. This means the number of + ions = number of - ions. Example: Ca(2+) Cl(1-) so you need 2 Cl(1-) to make the charges equal.
Acids	In water they give a pH of less than 7. Common acids: sulphuric acid, hydrochloric acid and nitric acid. H+ ion (proton) is the active ingredients, responsible for all acid reactions. An acid is a proton donor.
Redox reaction	Oxidation: loss electrons (agent: removes) Reduction:

Resource summary

	Created by Jess Drane almost 10 years ago