Inorganic Group 1&2

G1 & G2:
- IE decreases down the group

- WHY? Shielding increases, Atomic radius increases SO energy required to remove an electron decreases

- Reactivity increases does the group
- WHY? Shielding increased, Atomic radius increases SO energy required to

remove an electron decreases so more reactive as lower Ea

- G1 W/ Oxygen

• -  Lithium (as expected) → 2Li2O

• -  Sodium (IF IN EXCESS O2) then as expected → 2Na2O

- IF NOT → Na2O2

• -  K & Rb (Superoxide) → KO2 or RbO2

• -  COLOURS: Red, Yellow, Lilac

• -  G2 W/ Oxygen

  • -  ALWAYS → 2X +O2 → 2XO

  • -  COLOURS: White/Colourless, Brick Red, Crimson Red, Green

• -  G1&G2 W/ Cl2

  • -  G1:2X+Cl2→2XCl

  • -  G2:X+Cl2→XCl2

  • -  ALL: white solids with reaction becoming more vigorous down the group

• -  G1 w/ Water

  • -  ALWAYS:X+H2O→XOH+H2

  • -  OBSERVE: Li floats moves dissolves effervescence

  • -  OBSERVE: Na forms a ball which skirts around the water surface and violet

    exothermic reaction

  • -  OBSERVE: K is very very exothermic and the hydrogen produced ignites in

    a lilac flame

  • -  THINK: If the odd compound is in the reactants the product is odd if not

    then as you would expect

• -  G2 w/Water

  • -  Beryllium no reaction

  • -  Mg + H2O → No reaction
    - IFSTEAM:Mg+H2O(g)→MgO+H2

  • -  THENALLSAME:X+2H2O→X(OH)2+H2

• -  G1 Oxides w/Water

  • -  Li2O + H2O → 2LiOH

  • -  Na2O2 + 2H2O → 2NaOH + H2O2 (if Na2O then same as above)

  • -  KorRb:2KO2+2H2O→2KOH+H2O2+O2(andsameforRb)

- THINK: Hydroxide, Peroxide, Peroxide Oxygen - G2 oxides w/Water

• -  MgO - No reaction

• -  ALL OTHERS: XO + H2O → X(OH)2

• -  TREND: Solubility increases down the group

- G1 Oxides w/dilute acid

• -  Li2O + 2HCl → 2LiCl + H2O

• -  Na2O2 + 2HCl → 2NaCl + H2O2

• -  K&Rb:2KO2+2HCl→2KCl+H2O2+O2

- THINK: Salt forms and the rest is the same trend as with Water - G2 oxides w/dilute acid

- ALL:XO+2HCl→XCl2+H2O
- REMEMBER: Mg reacts here!!

• -  G1 & G2 Hydroxides w/dilute acid

  • -  ALL: XOH or X(OH2) + Acid → Salt + Water

  • -  G1:LiOH+HCl→LiCl+H2O

  • -  G2: Ca(OH)2 + 2HCl → CaCl2 + 2H2O

• -  Solubility: Hydroxides

  • -  Increased down group 1 and 2

  • -  G1 more soluble so solutions more alkaline

• -  Solubility: Sulphates:

- Decreases down groups (Group 1 ALL Soluble)

• -  Thermal Stability Carbonates and Nitrates:

  • -  Carbonates decompose to give CO2 and the metal oxide

  • -  Nitrates (NO3) decompose to give NO2 (BROWN GAS) and the metal oxide as

    well as 1⁄2 O2

  • -  Thermal stability increases down the group

  • -  Group 2 less table than corresponding Group 1

  • -  EXPLANATION: Polarising Power - extent to which positive ion distorts the

    negative. The larger the charge and the smaller the positive ion (as the nucleus is ‘closer’) the greater the negative ion is distorted. With heavy distortion the ions are easier to break apart and thus less stable. A larger charge and smaller ionic radius has a high charge density and as a result a better polarising power. The metal ion cna polarise the negative electron cloud which makes the compound easier to break apart

  • -  REMEMBER: Large cation more stable

• -  Flame Colours: Formed as a result of energy causing electron promotion to a higher

  energy level, the electron cannot sustain being at this level and thus return down releasing energy in doing so. If the energy released is on the visible spectrum we will see it as a flame colour

  • -  REMEMBER: Li - Red, Na - Yellow, K - Lilac

  • -  Remember: Mg - none/colourless/white, Ca - Brick Red, Sr - Crimson Red, Ba -

    Green