NATURAL Sciences Term 2

• Elements

  • Hydrogen (H)
  • Helium(He)
  • Lithium(Li)
  • Beryllium(Be)
  • Boron(B)
  • Carbon(C)
  • Nitrogen(N)
  • Oxygen(O)
  • Fluorine(F)
  • Neon(Ne)
  • Sodium(Na)
  • Magnesium(Mg)
  • Aluminium(Al)
  • Silicon(Si)
  • Phosphorous(P)
  • Sulfur(S)
  • Chlorine(Cl)
  • Argon(Ar)
  • Potassium(K)
  • Calcium(Ca)
• Atomic number


  The number of protons in the nucleus of an atom
• Atom


  The building blocks of matter
• Subatomic particles in an atom

  • Electrons
  • Protons
  • Neutrons
• Electrons


  • Orbit around the nucleus
• Protons


  • Positively charged particle in the nucleus
• Neutrons


  • Neutral particle in the nucleus
• Remember PEN: Protons, Electrons, Neutrons
• Atomic number


  Number of protons
• Atomic number

  Same as number of protons and number of electrons
• To calculate number of neutrons: Atomic mass - Atomic number
• Chemical symbols


  • Every element has a unique symbol
  • Symbol is usually the first 1-2 letters of the element name
  • First letter is always capital
  • Second letter is always lowercase
  • Some symbols come from Latin names
• Compound


  Two different elements bonded together in a fixed ratio
• Mixture


  Two or more substances combined but not chemically joined
• Solution


  A homogeneous mixture where a substance is dissolved into another substance
• Solute


  The smaller part of a solution that is being dissolved
• Solvent


  The larger part of a solution that the solute is dissolved in
• Diatomic molecules


  • Hydrogen (H2)
  • Oxygen (O2)
  • Nitrogen (N2)
  • Fluorine (F2)
  • Chlorine (Cl2)
  • Bromine (Br2)
  • Iodine (I2)
• Particle model of matter


  • Matter is anything with mass and volume
  • Matter is made of tiny particles (atoms)
  • Particles are constantly moving
  • There are forces of attraction and repulsion between particles
• States of matter


  • Solid
  • Liquid
  • Gas
• Solid


  • Particles tightly packed in regular arrangement
  • Strong forces between particles
  • Particles vibrate
• Liquid


  • Particles loosely arranged
  • Particles slide over each other
  • Weaker forces between particles
• Gas


  • Particles in no arrangement
  • Particles move very fast
  • Very weak forces between particles
• Phase changing processes


  • Melting
  • Freezing
  • Evaporation
  • Condensation
  • Sublimation
• Melting point


  Temperature when a solid changes to a liquid
• Boiling point


  Temperature when vapour pressure equals atmospheric pressure
• Condensation point


  Temperature when a gas changes to a liquid
• Reactants yield products in a chemical reaction
• Ways to detect a chemical reaction

  • New substances formed
  • Changes in properties (color, precipitate, gas produced)
  • Change in energy (endothermic or exothermic)
• Synthesis reaction


  Two or more simple substances combine to form a more complex substance
• Decomposition reaction


  A more complex substance breaks down into simpler parts
• Naming compounds


  • Metal comes first, non-metal second
  • Non-metal name changes to end in -ide
• Synthesis reaction


  Two or more reactants yielding one product
• Synthesis reaction


  • H₂+O--→→ H₂O
• Decomposition reaction


  A more complex substance breaks down into its more simple parts. One reactant yields 2 or more products.
• Decomposition reaction


  • 2 H₂O₂
• Naming compounds


  Compounds that contain a metal and a non-metal: The metal comes first and the non-metal second. The name of the non-metal changes slightly: the suffix -ide replaces the ending of the name.
• Naming compounds


  • NaCl - Sodium chloride
  • FeS - Iron sulfide
  • MgO - Magnesium oxide
  • LiF - Lithium fluoride
• Balancing reactions


  Never change the subscript (the small number behind the element), only change the coefficients (the numbers in front of the molecule or compound)
• Atoms are the fundamental particles that all matter is made up of