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Group 1 & 2 - Coggle Diagram

- - - - melting --> change in state
        decomposes --> chemical breakdown
  - - - small charge/size cation --> more polarising/electron cloud of anion is more distorted -->
        weakened anion bonds --> break down more easily
        
        this is why thermal stability increases down group 2
  - - - Group 2
        
        all group 2 nitrates decompose with brown fumes (forms metal oxide)- this means that group 2 has a greater level of decomposition
        
        2Be(NO3)2 --> 2BeO +4NO2 +O2
        
        this is because they are small cations with a high charge
      - Group 1
        
        only lithium decomposes with brown fume (forms metal oxide) due to smaller size
        
        4LiNO3 --> 2Li2O +4NO2 +O2
        
        sodium down : forms metal nitrite - lesser decomposition
        
        2NaNO3 --> 2NaNO2 + O2
      - greater decomposition occurs when the cation has a 2+ charge or when a 1+ charge cation is small (only lithium)
      - The nitrates are white solids, and the oxides produced are also white solids.
  - - - If they decompose, they will give off carbon dioxide although no observations can be made as the oxide is also a white solid and carbon dioxide is colourless
        metal carbonate --> metal oxide + carbon dioxide
        
        same trend as nitrates
        
        group 1
        
        only lithium carbonate will decompose on heating
        LiCO3 --> Li2O + CO2
        
        group 2
        
        all group 2 carbonates will decompose
        CaCO3 --> CaO + CO2
        
        greater decomposition occurs when the cation has a 2+ charge or when a 1+ charge cation is small (only lithium)
        
        All of these carbonates are white solids, and the oxides that are produced are also white solids.
- - - - Ba is stored under oil to protect them from reacting with oxygen and water vapour in the air
- - - - Lithium:
        
        fizzing
        
        floats on the surface
        
        sodium:
        
        fizzing
        
        sodium melts into a silvered coloured ball
        
        ball of sodium moves on the surface
        
        Potassum:
        
        fizzes more vigourously
        
        lilac flame
        
        moves around more quicky
        
        General equation:
        metal + water --> metal hydroxide + hydrogen
        2M (s) + 2H2O (l) --> 2MOH (aq) +H2 (g)
  - - - General equation:
        metal + water --> metal hydroxide + hydrogen
        M (s) + 2H2O (l) --> M(OH)2 (s) +H2 (g)
        
        this is a redox reaction
      - magnesium reaction with steam
        
        magnesium + water --> magnesium oxide + hydrogen
        Mg (s) + H2O (g) --> MgO (s) +H2 (g)
        
        the hydrogen gas is burned as it leaves the tube to avoid a highly flammable gas from going into the lab
- - - - so ionisation energy decreases
- - - - simplified ionic equation
        O2- + H2O --> 2OH-
        
        OH- makes the resulting solution have a pH value > 7
        
        the pH value will depend on the solubility of the metal hydroxide
        
        The solubility of metal hydroxide increases down the group which in turns causes the maximum alkalinity (pH value) of the solutions formed to increase (bc of increased concentration of OH- ions produced when solubility increases)
        
        e.g
        
        Magnesium hydroxide is insoluble but barium chloride is soluble
        
        Since reactivity decreases down the group, the reaction of oxides varies down the group
- - - - E.g
        metal oxide (s) + acid (aq) --> salt (+ water
        Na2O + H2SO4 --> Na2SO4 + H2O KOH + HCl --> KCl + H2O
- - - - The low solubility of barium sulfate is the reason that it is used as:
        
        the chemical test for sulfate ions
        
        or in barium meals to allow soft tissues to show up on x rays
        
        Ba2+ (aq) + SO42- (aq) --> BaSO4 (s)
- - - - Dip in clean platinum or nichrome wire into concentrated HCl
        
        Dip the wire into the ionic solid to be tested
        
        Place the wire/solid in to a roaring blue flame on a Bunsen burner and observe the colour
    - - many ionic compounds contain sodium impurities which burns with an intense orange colour that can obscure the actual flame colour
        .
        
        describing colours is very subjective
    - - the colour in flame tests in caused by electron transitions between energy levels
        .
        
        electrons can absorb energy and move to higher energy levels (excitation/promotion)
        .
        
        the electron then falls back down to its ground state (original energy level) and releases the energy it absorbed (as light)
        .
        
        Energy released is a photon of visible light corresponding to a specific wavelength
        .
        
        if the wavelength is within the visible region (400nm-800nm), then the characteristic colour appears
        .
        
        metals such as magnesium release radiation in the UV region, therefore they appear colourless to our eyes
- - - - when sodium hydroxide is added and the mixture is warmed, the ammonium reacts to form ammonia gas
        .
        
        ammonia gas will turn damp red litmus paper a blue colour
        
        NH4+ + OH- :arrow_right: NH3 + H2O
    - - Mix ammonia with hydrogen chloride to form a white solid
        NH3 + HCl --> NH4Cl