Chemistry yr 10 2024

• Atom


  In the centre of an atom there is a nucleus made up of subatomic particles (protons and neutrons)
• Atoms


  Identified by the number of protons and electrons
• Mass number


  Protons + neutrons
• Octet rule


  Atoms want 8 valence electrons to be stable
• Ion


  An electrically charged atom
• Anion


  Atom that has gained electrons and is negatively charged
• Cation


  Atom that has lost electrons and is positively charged
• Atoms form ions


  To make noble gases and to be more stable
• Metals


  • Made of giant lattices
  • Metal ions are tightly packed together making them a dense material
  • De-localised electrons in the metal slip under one another
• Metals


  When heated, protons and electrons move faster creating friction to produce heat
• Metal oxides


  Are bases
• Properties of metals


  • Malleable
  • Ductile
  • Lustrous
  • Conductor
  • High melting points
• Alkali


  Any base that dissolves in water
• Alkaline


  Substances with a pH higher than 7
• Halogens


  Group 17 elements with 7 electrons in their outer shell (unstable)
• Halogens


  • Highly reactive
  • Poor conductors
  • Dull
  • Brittle
• Noble gases


  Group 18 elements with a full outer shell (stable)
• Noble gases


  • Colourless
  • Odorless
  • Tasteless
  • Non-flammable
• Ionic compounds


  Mixture of metals and non-metals
• Arrow in chemical equations

  Reads 'produces' since it points to the final condition of the substance
• Equal chemical equations


  Mass of reactants = mass of products
• Reactants


  The left side before the reaction
• Products


  The right side after the reaction
• Word equations


  Chemical equations written using formulas, coefficients, and arrows
• Symbols in chemical equations

  • +

  ;

  Overcrossing arrows

  (s)

  (l)

  (g)

  (aq)
• Combination (synthesis) reaction


  2 separate chemicals are combined to form 1 compound
• Decomposition reaction


  1 compound breaks down into 2 separate substances
• Single displacement reaction


  A single element is placed into an ionic compound solution, and the element replaces one of the parts of the solution
• Double displacement (precipitation) reaction


  2 ionic solutions are mixed, the ions interact with each other and produce an insoluble ionic solid in an ionic solution
• Combustion reaction


  All hydrocarbons will combust when set alight in the presence of oxygen
• Soluble


  Able to dissolve, especially in water
• Insoluble


  Not able to dissolve
• Precipitation reaction


  A special case of a double displacement reaction where 2 soluble reactants combine to form an insoluble product known as a precipitate
• Factors affecting rate of reaction

  • More pairs of particles need to be active (higher concentration)

  Higher temperature

  Larger surface area

  Pressure

  Catalyst (surface)
• Collision theory


  Particles must collide, with correct orientation, and sufficient energy