Atomic Structure & Periodic Table

Atomic Structure & Periodic Table

1. ATOMS

   • All substances are made from atoms
   • Contain:
     • Nucleus
       • Neutrons
         • Neutral/no charge
         • Very heavy
       • Protons
         • +1 Positive charge
         • Very heavy
       • Positively charged
     • Electron shells
       • Electrons
         • Very small
           • But cover lots of space
           • Virtually no mass
         • -1 negative charge
   • NO. protons = NO. electron
     • No charge
     • Cancel each other out

2. ELEMENTS

   • Nuclear symbol
     • Atomic Number
       • NO. protons
         • Define what element the atom is
     • Mass Number
       • NO. protons & neutrons
     • Neutron amount
       • Mass number-Atomic number
   • Consisting of atoms with same atomic number

3. ISOTOPES

   • Different forms of same element
     • Same NO. protons
     • Different NO. neutrons
     • Same atomic number
     • Different mass numbers
   • Relative Atomic Mass
     • Used instead of mass number
     • Average mass & quantity of all isotopes that make up an element
     • RAM = (isotope quantity X isotope mass number) ÷ quantity of all isotopes

4. COMPOUNDS

   • Atoms join together to form these
   • Two or more elements react, atoms combine
     • Held together by chemical bonds
   • Metal & Non-metals
     • Metals lose atoms
       • Forming positive ions
     • Non-metals gain electrons
       • Forms negative ions
     • Ionic bonding
   • Non-metals
     • Each atom shares an electron with another atom
     • Covalent bonding
     • Consists of molecules
   • Usually completely different to original elements

5. CHEMICAL EQUATIONS

   • Shows chemical changes
   • Word equations
     • Molecules on right
       • reactants
     • Molecules on left
       • Products
   • Symbol equations
     • Need to be balanced!!
       • Same amount of elements on each side
         • only add big numbers, in front

6. MIXTURES

   • lots of separate things all mixed toghether
   • easily separated
     • unlike componds
     • no chemical bonding
   • made up of elements and compounds
   • separated my physical methods
     • filtration
     • crystalisation
       • Crystalisation--PRACTICAL
       • Rock Salt
         • Separating rock salt--PRACTICAL
     • simple distiallation
     • fractional distillation
     • chromatography
       • Paper Chromatography--PRACTICAL
   • Examples
     • air
       • nitrogen
       • oxygen
       • carbon dioxide
       • argon
       • these gasses can be separated fairly easily
     • Crude Oil
       • mixture of different length hydrocarbons
   • properties
     • a mixture of the properties of the separate parts
     • the chemical properties of a substance are not affected
     • example
       • iron powder & sulphur powder
         • show properties of both
         • grey magnetic bits and yellow bits
           • iron
           • sulphur
         • mixed but not react
   • PRACTICLES
     • Paper Chromatography

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