Chemistry

• Atom


  The basic unit of a chemical element
• Element


  Made up of atoms of the same kind
• Compound


  Made up of two or more different elements chemically bonded together
• Pure substance


  Consists of only one type of material and is not mixed with anything else
• Elements and compounds are both pure substances
• Atom


  • The smallest building block of matter
• Atoms make up elements
• Every element has a name and a symbol
• All the elements are listed in the Periodic Table

  
• Compound


  Formed when two or more elements are chemically bonded together
• A pure substance consists of only one type of material and is not mixed with anything else
• Elements and compounds are pure substances because they consist of only one type of material
• Periodic Table


  A classification system for the elements

  
• Element


  A pure substance that cannot be broken down further
• Elements


  • Copper
  • Gold
  • Oxygen
• Categories of elements


  • Metals
  • Non-metals
  • Semi-metals
• Group


  A vertical column on the Periodic Table
• Formula


  The ratio of the symbols of the elements and the number of atoms for each symbol in a compound
• The metals are found in the middle and on the left-hand side of the Periodic Table
• The non-metals are found in the middle and on the right-hand side of the Periodic Table
• The semi-metals are found in a zig-zag line between the metals and the non-metals
• Compound name ending in 'ide'


  Indicates two elements in the compound
• Compound name ending in 'ate'


  Indicates three elements in the compound, one of which is oxygen
• Common compound names


  • Water (H2O)
  • Ammonia (NH3)
• Formula


  Tells you the symbols of the elements in the compound and the ratio of the number of atoms of each element
• Many compounds are named according to their elements
• Compounds are made of elements that are chemically bonded (joined together)
• The elements in compounds are the elements found in the Periodic Table
• Chemical reaction


  A process that occurs when two or more substances react to form new substances
• Reactants


  The substances that react in a chemical reaction
• Products


  The substances that are made as a result of a chemical reaction
• Subscript


  Indicates the number of atoms of an element in the compound
• Numbers in front of formulae

  Indicate the ratio in which the molecules react
• No atoms are lost or gained in a chemical reaction, they are just rearranged
• Balanced equation


  Has the same number of atoms on each side of the reaction arrow
• No atoms are lost or gained in a chemical reaction, they are just rearranged. This is called the Law of Conservation of Matter.
• Balancing a chemical equation

  Changing the number of molecules or atoms to conserve the matter in the reaction
• You cannot change the composition of a molecule or atom in order to balance a chemical equation, but you can change the number of molecules or atoms
• Metal


  A material that conducts electricity, and which is malleable and shiny
• Oxygen


  Colourless and odourless gas that makes up about 20% of the atmosphere