chemistry gr10 term 2

chemistry gr10 term 2

1. the atom

   • neutrally charged
     • same amount of protons and electrons
       • protons are postively charged
         • the amount always remains constant
       • electrons are negatively charged
         • can be gained or lost
           • the valence number indicates how many electrons can be gained, lost or shared
       • an ion is a charged atom
         • - an anion is a negative ion -
         • + a cation is a postitve ion+

2. mixtures

   • a combination of 2 or more substances that arent chemically joined or bonded. no chem reaction.
     • -no fixed ratio -keep their physical properties -dont create a new substance -can be seperated mechanically
       • heterogeneous mixtures
         • components stay seprate
           • 'non-uniform"
         • eg: milk and cereal, sand and water, soil and pebbles
         • types:
           • liquid-liquid = emulsion
             • oil and water
           • solid-liquid = suspension
             • muddy water
           • gas-liquid = aerosol
             • fizzy drink
           • gas- solid = smoke
             • smog
       • homogeneous mixtures
         • the mixture has "become one"
           • diferent parts can't be seen seperatelyy
             • "uniform"
         • eg: salt disolved in water
       • chromatography is a proccess that seperates different componenets of a substance

3. periodic table

   • values
     • the largest value is the mass number (or atomic mass)
       • tells us the amount of protons and neutrons
         • N=A-Z
         • Z
         • determines the mass of the atom
     • 2nd largest value is the atomic number
       • tells us the amount of protons
         • N=A-Z
           • N = neutrons
         • A
         • *always the same in an element of the same atom
   • layout
     • groups are verticle
       • nr of valence electrons are the same as the group number
     • periods are horizontal
       • tells us the how many orbitals in an element

4. bonds

   • covalent bonds
     • polar
       • the elements have an electronegativity difference of more than 0
         • the higher the EN, the stronger this type of bond is
     • non-polar
       • EN difference of 0
     • *both nonmetals
   • ionic bonds
     • cations and anions (not H+)
       • very strong bond
         • ionic compounds have a strong boiling and melting point
         • electrostatic
       • metal and nonmetal
     • ions are arranged in a lattice structure
       • most are solid at room temp
         • its only a conductor in solutions
   • metallic
     • valence electons are delocalised
       • electrostatic
     • between 2 mentals
   • • when forming bonds energy must be released
     • when breaking bonds, energy bust be absorbed
   • depends on distance between atoms

5. forces

   • intra-molecular (interatomatic)
     • inside the molecule
       • covalent
         • polar
         • non-polar
       • ionic
       • metallic
   • inter-molecular
     • between the molecules
     • dipole-dipole
     • hydrogen bond
     • induced dipole force (london forces/ dispersed forces)
       • van der waals forces

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