Chemistry AS Revision

Chemistry AS Revision

1. Atomic Structure

   • Locate The Groups and The Groups Charecteristics
   • All Material things are made up of Atoms
     • Over 100 Types of Atoms Called Elements
   • The mass number is equal to the number of protons and neutrons

2. Ionic Compounds

   • Electrically charged particles, Made when Atoms loose or gain Electrons
   • Metal Atoms loose electrons, to become Positively Charged Ions
     • Non Metal Atoms gain Electrons to become Negatively Charged Ions
       • Dot and cross Diagrams to show ions in some common Compunds
       • Compounds such as Sodium Chloride are arranged in a 'Lattice'

3. Covalent Compunds

   • Non-Metals combine together by sharing Electrons
     • Giant Molecular Compunds
       • Contains Non-Metal Atoms
         • Characteristics
           • High Melting Points
             • Variable Conductivity
   • Dot and Cross diagrams Show how pairs of Bonds Form
     • Simple Molecular Compounds
       • Only a few atoms held by strong covalent Bonds
   • Covalent Bonds do not Conduct Electricity.

4. Periodic Table

   • A Table of Metals and Non Metals
     • Arranged in the order of Atomic Numbers
       • Different Groups contain Elements with similar Propities
       • Using Atomic Number instead of Atomic Mass as the organising principle Was first proposed by...
         • Henry Moseley
     • Russian Chemist Called Dmitri Mendeleev, Discovered a sensible way to order Elements
       • Mendeleev Put them in order of Relative Atomic Mass

5. Chemical Reactions

   • Endo and Exo Reactions
     • Endothermic
       • Take in Energy from the Surroundings
         • Examples =
           • Electrolysis
             • Photosynthesis
     • Exothermic
       • Transfer Energy to The surroundings
         • Examples =
           • Combustion (Burning)
             • Neutraliastion

6. Quantitative Chemistry

   • Relative Atomic Mass [Ar]
     • Relative Formula Mass
       • Example 1:
         • Find the [Mr] of carbon monoxide, {CO}. The [Ar] of Carbon is 12, and The [Ar] of Oxygen is 16, So the [Mr] is 12 + 16 = 28
           • In all Chemical reactions, The total Reactants used is equal to the total mass of the products made
   • Empirical Formulae
     • Method
       • Find Mass
         • Look Up Relative [Ar] Values
           • Divide MASS by Ar
             • Find The Ratio
             • IMPORTANT - Take Caution

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