AQA Chemistry [C2] Part 1

AQA Chemistry [C2] Part 1

1. Bonding

   • Ionic
     • Metals and non-metals
       • Metals
         • Lose electrons
           • Positive ions
       • Non-metals
         • Gain electrons
           • Negative ions
     • Compounds held by strong forces
     • Giant stucture or lattice
       • Strong electrostatic forces
         • Each ion surrounded by ions of the negative charge
           • Held firmly in place
   • Covalent
     • Non-metals
       • Two atoms share electrons
     • Group 7
       • Gain one electron
         • Form single bond
   • Metallic
     • Electrons in highest energy shell delocalise
       • Move freely between each other
         • A lattice of + ions in a sea of moving electrons
           • Delocalised electrons attract

2. How much?

   • Reversible reactions
     • Products react to make original reactants
   • Analysing substances
     • Identify food additives
       • Paper chromatography
         • Detect artificial colours
           • Solvent is allowed to move through the paper
         • Compounds separated using gas chromatography
           • Identified using a mass spectrometer
             • Find relative molecular mass
               • From its molecular ion peak

3. Structure and Properties

   • Giant ionic structures
     • Strong electrostatic forces
       • Solid at room temperature
         • High melting and boiling point
     • Conduct
       • Molten
         • Ions free to move
       • Water
         • Water molecules split lattice
   • Simple molecules
     • Low melting and boiling point
       • Intermolecular forces are weak
     • Do not conduct
       • No overall charge
   • Giant covalent structures
     • Very high melting points
     • Diamond
       • Form of carbon
         • Carbon atom bonded with four other carbon atoms
           • Makes diamond hard
           • Transparent
     • Graphite
       • Carbon atom bonded with three other carbon atoms
         • No covalent bonds
           • Slide over each other
             • Weak intermolecular bonds
               • Graphite = slippery and grey
         • One electron is delocalised
           • Allow graphite to conduct heat and electricity
   • Giant metallic structures
     • Alloys
       • Mixtures of metals
         • Different sized atoms
           • Distort the layers
             • More difficult to slide
       • Harder than pure metals
       • Shape memory alloys
         • Bent/ deformed into different shape
     • Conduct heat and electricity
       • Delocalised electrons
   • Polymers
     • Depends on the monomers
     • Thermosetting polymers
       • Do not soften or melt
     • Thermosoftening polymers
       • Forces are weak
         • When heated, polymer becomes soft
           • Weak intermolecular forces are broken
   • Nanoscience
     • Study of small particles
       • Very large surface area