Definition of an elementDefinition of an element
• An element is a substance that cannot be made into anything simpler by means of a chemical reaction.
• The atoms of an element all have the same numbers of protons. There are over a hundred different elements and they are arranged in the periodic table.
Definition of a compoundDefinition of a compound
• Compounds contain more than one element.
• The elements in a compound are not just mixed together: they are joined by strong forces called chemical bonds.
• You will not find any compounds in the periodic table.
• Compounds do not have the same properties as the elements they contain.
• A compound is a substance that can be made into something simpler by means of a chemical reaction.
• Sodium metal is very reactive
• Chlorine is a poisonous gas.
• They combine to form sodium chloride which has different properties.
• It is non poisonous and non reactive.
Why do elements form compoundsWhy do elements form compounds
• Atoms tend to have the maximum number of electrons in their outer levels.
• They achieve this by bonding with other atoms.
Electron will move from Na to Cl
Ionic CompoundIonic Compound
• An ionic compound is made up from metals and non metals.
• The metal will be written before the non metal.
• CaF2 MgO NaCl K2S
Naming Ionic compoundsNaming Ionic compounds
• The name of the metal will not change• The name of the non metal will
change into the “root of the word + ide”
• Oxygen will change into oxide• Sulphur will change into sulphide• Chlorine will change into chloride