GCSE science - full recap (atoms, elements and compounds)

• Hydrogen is a non-metal
• non- metals are towards the right and top

  A)

  
• metals are towards the left and bottom
• Silicon = Si
• Magnesium = Mg
• Silver = Ag
• Carbon = C
• Iron = Fe
• Sulfur = S
• Lithium = Li
• Oxygen = O
• Nitrogen = N
• Copper = Cu
• An atom is the smallest part of an element that can exist
• An element is a pure substance made from only one type of atom
• A compound is a substance made up of two or more elements that are chemically bonded together
• Iron oxide = Iron and oxygen
• Hydrogen sulphide = hydrogen and sulphur
• Lithium chloride = Lithium and chlorine
• Carbon dioxide = Carbon and oxygen
• Carbon monoxide = Carbon and Oxygen
• Water = hydrogen and oxygen
• Magnesium sulphate = Magnesium, sulphur and oxygen
• The minimum number of elements in a compound is 2
• Atoms are conserved during a chemical reaction, since they can't be created or destroyed
• The number of atoms for each element in the reactants and in the products of a reaction are the same
• A mixture is 2 or more different elements or compound that are not chemically bonded together
• Filtration is used to separate an insoluble solid from a liquid
• The equipment used in filtration:

  • Filter paper
  • Funnel
  • Conical flask
• For filtration to work the holes in the filter paper must be smaller than the solid particles to prevent them from passing through
• Residue is the insoluble solid left on the filter paper
• Filtrate is the liquid that passes through the filter paper
• Evaporation is separating a soluble solid from a solution
• Crystallisation is used to separate and collect a soluble solid from the solvent, by making crystals
• Chromatography is separating soluble substances from one another in a mixture (e.g mixtures of inks & dyes)
• Substances in the mixture that are more soluble in the solvent being used, will travel further up the chromatography paper
• A solute is a solid or has that dissolves into a liquid
• Solvent is the liquid in which a solid or gas dissolves
• A solution is a mixture of solid or gas dissolved in a liquid that can be separated out
• Interpreting chromatograms:

  • The number of spots vertically above the original spot is the number of substances in that mixture
  • Spots that match horizontally are the same substances