Periodicity

• Name and write the equation(process) both hydroxides undergo.

  Neutralisation

  H+(aq)+OH−(aq)⇋H2O(l)
• What are all the soluable salts?

  Group 1 salts,ammonium salts(chloride/ sulfate) and all nitrates.
• Which elements are in s-block

  group 1 and 2 including hydrogen
• which elements are in p-block


  non-metals
• which elements are in d-block


  transition metals including helium
• how are elements classified in each block

  classified according to which orbitals the highest energy electrons are in.
• trend for atomic radius(period 3)

  atomic radius decreases across period because:

  -more protons so nuclear charge increases=stronger attraction between nucleus and outer e-
• trend for ionisation energy(period 3)


  increases across period but dips in group 2-3 and 5-6

  -group 2-3 dip: Mg and Al-easier to remove electron in 3-p orbital (Al) --than 3s orbital(Mg) so IE decreases

  group 5-6 dip: repulsion in sulfur(3porbital)means electrons are easier to remove so IE decreases
• trend for electronegativity(period 3)

  -increases because:

  -more protons

  -atomic radius decreases so greater attraction between shared pair of electrons and nucleus
• MP and BP(period 3) [take into account of each atoms...]

  -overall increases across period 3

  -Na and Mg:metallic bond gets stronger.Higher charged ions so more electrons delocalised per ion.Therefore,stronger attraction between oppositely charged ions and electrons that require more energy to break.

  -Si-giant covalent strcuture.Lots of strong covalent bonds to be broken.

  • P to Ar(P4,S8,Cl2,Ar)-simple covalent/molecular.weak van der waals between molecules, so little energy is needed to break them – low mp+ bp S8 has a higher mp than P4 because it has more electrons (S8 =128)(P4=60) so has stronger v der w between molecules Ar is monoatomic weak van der waals between atoms
• when comparing compounds in period 3 you need to discuss:the structure(simple covalent,ionic lattice ect,bonding and intermolecular forces)
• When comparing ionisation energies of elements looks at the block it's in and whether there's repulsion e.g.

  Al+→Al2+ + e- vs Li+→Li2+ + e-

  -more energy required for lithium as aluminium is in 3p easier to remove
• sodium reaction with water

  2Na (s) + 2H₂O(l) →2NaOH (aq) +H₂(g)

  vigorous reaction,yellow flame and fizzing observed.Strong alkaline solution produced.
• All reactions in period 3=redox
• Magnesium reaction with water:

  Mg(s)+2H₂O→Mg(OH)₂ (aq) +H₂(g)

  -reaction slow at room temp.few hydrogen bubbles observed
• Magnesium reaction with steam

  Mg(s) +H₂O(g)→MgO(s)+H₂(g)

  -faster reaction.White solid and bright light observed.
• Sodium reaction with oxygen:

  4Na(s)+O₂(g)→2Na₂O(s)

  -yellow flame and white powder observed
• Magnesium reaction with oxygen:

  2Mg(s)+O₂(g)→2MgO(s)

  -white flame,forms white solid smoke as observed
• Aluminiumreaction with oxygen

  4Al(s)+3O₂(g)→2Al₂O₃(s)

  -burns with white and white solid smoke formed
• Silicon reaction with oxygen

  Si(s)+O₂(g)→SiO₂(s) burns with a white flame,white solid smoke formed.
• Phosphorus reaction with oxygen:

  4P(s)+5O₂(g)→P₄O₁₀(s) (when oxygen is in short supply p4O5 made)

  -burns with a white flame,white solid smoke observed.

  -red phosphorous must be heated before it will react with oxygen but white phosphorus ignites spontaneously in air.
• Sulfur reaction with oxygen:2S (s)+3O₂(g)→2SO₃(g)

  S (s) + O2 (g)  SO2 (g) burns with a blue flame to form an acidic choking gas.
• reactions with water=hydroxide produced

  reactions with oxygen-oxides produced
• Na₂O,MgO,Al₂O₃ bonding,structure,mp

  Ionic lattice structure.Ionic bonding.Strong electrostatic forces of attraction=high mp.

  BUT aluminium oxide has some covalent character
• sodium oxide,aluminium oxide,MgO structure,bonding and mp

  Ionic lattice structure.Ionic bonding.Strong electrostatic forces of attraction=high mp. Al₂O₃ has some covalent character.
• SiO₂

  Giant covalent structure.Lots of strong covalent bonds=high mp
• P₄O₁₀

  -Simple covalent structure(covalent bonding).More electrons=stronger van der waals forces-this is what mp depends on.
• SO₂,SO₃

  Simple molecular.(same reasoning as phosphorus oxide).sulfur trioxide is higher mp than sulfur dioxide as it has more electrons.
• when comparing mp between simple molecular check which has more electrons
• Which oxides don't react with water

  Al₂O₃ SiO₂

  -SiO₂ has a giant covalent structure which prevents it from dissolving in water or reacting with water(water can't break down its structure).It only reacts with concentrated NaOH
• sodium oxide reaction with water and PH

  Na₂O(s)+H₂O(l)→2Na+ (aq)+2OH-

  PH=13-14
• Magnesium oxide reaction with water and PH

  MgO(s)+H₂O(l)→Mg(OH)₂(s)

  PH=9
• which oxides react with acids and which with bases?

  -oxides sodium to aluminium react with acids(aluminium oxide reacts w both)

  -oxides aluminium to sulfur trioxide react with bases
• P₄O₁₀ reaction w water,PH

  P₄O₁₀ +6H₂O(l)→4H₃PO₄(aq)

  PH=1-2
• P₄O₁₀ acid produced after reaction w water and structure

  PO₄3- (acid) ,tetrahderal structure

  
• SiO₂-structure,bonding and mp

  Giant covalent structure.Lots of strong covalent bonds-high mp
• P₄O₁₀ , SO₂ , SO₃-structure,bonding and mp

  simple covalent structure(has covalent bonding).MP depends on strentgh of van der waals forces.More electrons=stronger van der waals=higher mp. but lowest compared to the other oxides.
• Which simple molecular compound is bigger SO₃or SO₂

  SO₃ bigger because it has more electrons so higher mp.
• Which oxides don't react with water?

  Al₂O₃ and SiO₂

  SiO₂-giant covalent structure can't be broken down by water so it can't dissolve in it.Only reacts with very concentrated NaOH
• sodium oxide reaction with water and PH

  Na₂O(s)+H₂O(l)→2Na+(aq)+2OH-(aq)

  PH=13-14