Matter and material

• Matter


  Everything around us and in us is made up of it
• Atom


  Extremely small particles that make up matter
• Components/particles/sub-atomic particles that make up an atom

  • Electrons
  • Protons
  • Neutrons

  
• Electrons


  • Negatively charged (-) particles found moving around the nucleus
  • Protons are positively charged (+) particles found in the middle inside the nucleus
  • Neutrons are uncharged particles (0 charge) found in the middle inside the nucleus with the protons

  
• Nucleons


  Protons and neutrons in the nucleus

  
• Matter with its atoms are found in nature as elements or compounds
• Element


  The simplest form of matter made up of identical atoms
• Examples of elements


  • Carbon
  • Silver
  • Gold
  • Oxygen
  • Hydrogen
• Periodic table


  A table that groups all the known elements on earth, arranged in order of increasing atomic number

  
• Atomic number


  The number of electrons or protons in an atom of the element
• Atomic mass


  The number of protons + neutrons in the nucleus

  
• Periodic table


  • Has vertical columns called groups
  • Has horizontal rows called periods
  • Elements within a group have similar chemical properties
  • Metals are on the left hand side
  • Non-metals are on the right hand side
  • Semi-metals are in the middle
  • Noble gases are in the last group and do not react
• Periodic table information to know

  • Horizontal rows are called periods
  • Vertical rows are called groups
  • Most metals are on the left hand side
  • There are 18 groups
  • The elements in group 18 are called noble gases/inert gases/stable gases
  • Hydrogen is the lightest element
  • The element in period 2, group 2 is Lithium
  • Semi-metals have properties of both metals and non-metals
  • The element below Oxygen is Fluorine
  • The scientist who designed the periodic table is Dmitri Mendeleev

  
• Molecule


  A combination of two or more atoms
• Atoms of elements do not exist as single atoms in nature, they combine to form molecules</b>
• Diatomic molecule


  An element that exists in nature as a molecule with two atoms of that element
• Define and give examples


  • Molecule: A combination of two or more atoms
  • Diatomic molecules: Oxygen, Hydrogen, Nitrogen

  
• Compound


  A substance made up of atoms of different elements chemically combined
• Examples of compounds


  • Water
  • Salt
  • Sugar
  • Carbon dioxide
• Chemical bond


  The force that holds the atoms in a compound together
• Representing chemical compounds


  1. Chemical formula: A way of representing the proportion of elements that are combined in a substance

  2. Sodium chloride (NaCl)

  3. Sodium (2Na) + Chlorine (Cl2) = Sodium chloride (2NaCl)

  
• Breaking down compounds


  1. Heating: Potassium permanganate (KMnO4) decomposes into Potassium manganate (K2MnO4), Manganese dioxide (MnO2) and Oxygen (O2)

  2. Electrolysis: Water (H2O) decomposes into Hydrogen (H2) and Oxygen (O2), Copper chloride (CuCl2) decomposes into Copper (Cu) and Chlorine (Cl2)

  
• Names of some common compounds

  • Sodium chloride (NaCl)
  • Potassium bromide (KBr)
  • Zinc oxide (ZnO)
  • Lithium oxide (Li2O)
  • Magnesium chloride (MgCl2)
  • Sodium sulphide (Na2S)
  • Sodium hydroxide (NaOH)
  • Calcium sulphate (CaSO4)
  • Iron sulphite (FeSO3)
  • Silver nitrate (AgNO3)
  • Copper carbonate (CuCO3)
  • Ammonium chloride (NH4Cl)
  • Hydrogen monoxide (H2O - water)
  • Sodium carbonate (NaHCO3 - baking powder)
  • Hydrogen sulphide (H2S - stink bomb)
  • Nitrous oxide (N2O - laughing gas)
  • Calcium sulphate (CaSO4 - plaster of paris)
  • Octane (C8H18 - petrol)
• Chemical reaction


  When two or more substances react with each other to form an entirely new substance with different properties
• Examples of chemical reactions

  • Digestion
  • Photosynthesis
  • Burning of wood
  • Rusting of iron
  • Brewing of beer
• Reactants


  Substances that react with each other
• Products


  The new substance formed
• Types of chemical reactions

  • Synthesis reaction: A + B → C + D
  • Decomposition reaction: C → A + B
• Chemical reactions take place all the time in our everyday life
• Information about chemical reactions

  • Reactants: Substances that react with each other
  • Products: The new substance formed
  • Two types: Synthesis reactions and Decomposition reactions
• Pure substance


  A substance made up of one kind of atom or molecule
• Examples of pure substances

  • Hydrogen (has only hydrogen atoms)
  • Salt (has only salt molecules NaCl)
  • Sugar (has only sugar molecules)
• Mixture


  A substance made up of different kinds of atoms or molecules or a combination of both that are not chemically joined
• Examples of mixtures


  • Iron filings and sulphur (two elements)
  • Oxygen and carbon dioxide (element and compound)
  • Sugar and salt (compound and compound)
• Differences between mixtures and compounds

  • Mixtures: Not chemically combined, each component retains its properties, can be separated by physical methods, components can be mixed in any proportion
  • Compounds: Chemically combined, product has different properties from reactants, can only be separated by chemical methods, elements in compound found in fixed proportion
• Information to know about pure substances and mixtures

  • Pure substance: A substance made up of one kind of atom or molecule
  • Examples of pure substances: Hydrogen, Salt, Sugar
  • Mixture: A substance made up of different kinds of atoms or molecules not chemically joined
  • Examples of mixtures: Iron filings and sulphur, Oxygen and carbon dioxide, Sugar and salt