Periodicity Period 3 Unit 5 AQA

• more reactive than magnesium
• burns with a yellow flame
• 2Na(s) + 2H₂O(l) --->NaOH(aq) + H₂(g)  - reaction with water
• 4Na(s) + O₂(g) --->Na₂O(s) - reaction with oxygen

Na₂O with water

• high melting points
• giant ionic lattice
• soluble and reacts with water
• alkaline - pH 14
• nature of oxide is basic
• Na₂O + H₂O --> 2NaOH
• ions present are Na+(aq) and OH-(aq)

• burns with a bright white flame
• Mg(s) + H₂O(g) --->MgO(g) + H₂(g)  - reaction with water
• 2Mg(s) + O₂(g) --->2MgO(s) - reaction with oxygen

MgO with water

• high melting points
• giant ionic lattice
• sparingly soluble and reacts with water
• slightly alkaline - pH 10
• nature of oxide is basic
• MgO + H₂O --> Mg(OH)₂
• ions present are Mg2+(aq) and OH-(aq)

• burns with a bright white flame
• 4Al(s) + 3O₂(g) --->2Al₂O₃(s) - reaction with oxygen

Al₂O₃ with water

• high melting points
• giant ionic lattice
• insoluble with water
• nature of oxide is amphoteric - pH 7

• burns with a bright white flame
• Si(s) + O₂(g) --->SiO₂(s) - reaction with oxygen

SiO₂ with water

• very high melting  and boiling points
• macromolecular
• strong covalent bond between atoms
• insoluble in water - pH 7

• burns with a bright white flame
• 4P(s) + 5O₂(g) --->P₄O₁₀(s) - reaction with oxygen

P₄O₁₀ with water

• lower melting points
• simple molecular
• weak intermolecular forces (VDW and Dipole Dipole)
• soluble and reacts with water
• slightly acidic - pH 1
• nature of oxide is acidic
• P₄O₁₀+ 6H₂O --> 4H₃PO₄
• ions present are H+(aq) and 4H₂PO₄-(aq)

• burns with a blue flame
• S(s) + O₂(g) --->SO₂(s) - reaction with oxygen

Na₂O with water

• lower melting points
• covalent molecular
• soluble and reacts with water
• acid
• nature of oxide is acidic
• SO₂ (g) + H₂O (l) --> H2SO₃ (aq)         pH 3 (weak acid)
  SO₃ (g) + H₂O (l) --> H2SO₄  (aq)        pH 1 (strong acid)
• ions present are H+(aq) and HSO₃-(aq) and H+(aq) and HSO₄-(aq)