chemical properties of period 3

• 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 powder as observed
• Aluminiumreaction with oxygen

  4Al(s)+3O₂(g)→2Al₂O₃(s)

  -white powder formed
• Silicon reaction with oxygen

  Si(s)+O₂(g)→SiO₂(s)
• Phosphorus reaction with oxygen:

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

  -white powder formed

  -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)
• 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
• 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
• Magnesium oxide reaction with water and PH

  MgO(s)+H₂O(l)→Mg(OH)₂(s)

  PH=9-10
• which oxides react with acids

  sodium oxide,magnesium oxide and aluminium oxide(which is amphoteric as it acts a base and acid)
• which oxides react with bases

  aluminium oxide onwards
• P₄O₁₀ reaction with water and the PH

  P₄O₁₀(s)+6H₂O(l)→4H₃PO₄(aq)

  PH=1-2 (an acid is produced)
• SO₃ vigorous reaction with water +PH

  SO₃(l)+H₂O(l)→H₂SO₄(aq)

  PH=0-1
• SO₂ reaction with water and PH

  SO₂(g)+H₂O(l)→H₂SO₃(aq)

  PH=2-3
• what is the trend for PH across period 3?

  PH of oxides decrease
• Which oxides behaviour are basic and which are acidic

  Mgo,Na2O-acidic

  P4O10,SO2,SO3-basic

  Al2O3-amphoteric(acidic and basic)
• trend for oxides reaction with water

  The trend is the ionic metal oxides show basic behaviour and the non-metal covalent oxides show acidic behaviour. The slightly intermediate nature of the bonding in Aluminium oxide is reflected in its amphoteric behaviour: it can act as both a base and an acid
• what do the ionic oxides form with water

  hydroxides
• what do the simple non-metal covalent oxides for with water

  they form acids
• ion produced from phosphorus oxide reaction w water+structureof anion

  PO₄3- ,tetrahedral structure

  
• SO₂ ion produced +structure


  SO₃2-,structure: triagonal pyramidal

  
• SO3 reaction with water ion produced +structure of acid produced

  SO₄2- -tetrahedral shape of ion

  
• Types of reactions for acids and bases with oxides

  Acid+metal oxide→salt+water

  Acid+alkali→salt+water

  Acid+carbonate→salt+water+CO2
• How do you name a salt?


  the first part of the salt name is the metal and then the 'ate' part from the acid