Elements

Elements

1. An element is a simple substance that cannot be split into anything simpler by chemical reactions

   • Atoms are the smallest particles of an element. Atomes of on element are all the same but are different from atoms of all the other elements

2. All the elements are shown in the periodic table

   • There are 117 known elements, each element has a chemical symbol, wich i usually one or two letters
     • A symbol is written with the first letter as a capital and the second letter in lower case, these are examples
       • Iron - Fe
       • Aluminium - Al
       • Oxygen - O
       • Carbon - C

3. Compounds

   • Elements can join together to make a compound
     • The name of the compound tells you the elements that are in it
       • Compounds made from two elements always have a name that ends in "ide"
         • Carbon + Oxygen = Carbon Dioxide
         • Sodium + Chlorine = Sodium Chloride
         • Magnesium + Oxygen = Magnesium Oxide

4. A chemical formula tells you the name and number of atoms in a compound, the smallest particle of many compounds is called a molecule

   • Molecules are made up of groups of atoms, some elements are also made of molecules, for example, a molecule of oxygen contains two atoms joined together - 02
     • Water contains two atoms of hydrogen and one of oxygen - H20

5. Metals and non-metals

   • The properties of a substance describe the way the substance behaves, or measurements that we can make on it. Metal and non-metals have different properties

6. Non-metals

   • Most are solids or gases
   • Dull
   • Brittle - Break easily and can not bend very well
   • Found on the right and middle of the periodic table
   • Poor conductors of heat and electricity

7. Metals

   • Good conductors of heat and electricity
   • Shiny
   • Solids with a high melting point
   • Mainly found on the left-hand side and in the centre of the periodic table
   • The metals are magnetic

8. Re-use and recycling

   • Materials can be classified to the properties.
     • All the different materials in the world are made up of about 90 different elements, some useful materials occur naturally, but others have to be manufactured using chemical reactions
       • In many cases, raw materials are non-renewable. If we can recycle these materials, then we reduce the demand for raw materials. There may also be energy saving as well
         • A process that used recycled or renewable materials is sustainable. Waste can also be reduced by re-using objects such as glass bottles or plastic bags