Period 3 elements

Equation for Na reacting with water and observations

• 2Na + 2H₂O→ 2NaOH + H₂

• Effervescence

• Large temp increase

Equation for Mg reacting with cold water and observations

• Mg + 2H₂O → Mg(OH)₂ + H₂

• Gentle fizzing

Equation of Mg reacting with steam and observations

• Mg + H₂O → MgO + H₂

• White solid

• White flame

Equation for Na reacting with oxygen and observations

• 4Na + O₂ → 2Na₂O

• Yellow flame

• White solid

Equation and observations for Mg reacting with Oxygen

• 2Mg + O₂ → 2MgO

• White flame

• White solid

Equation and observations for Al reacting with oxygen

• 4Al + 3O₂ → 2Al₂O₃

• White flame (Less bright than Mg)

• White solid

Equation and observations for P reacting with oxygen

• P₄ + 5O₂ → P₄O₁₀

• White flame

• White solid

Equation and observation of S reacting with oxygen

• S + O₂ → SO₂

• Blue flame

• Fumes of pungent gas

What are the structures of Na₂O, MgO and Al₂O₃

• Giant ionic lattice

Structure of silicon SiO₂

Giant covalent

Structure of P₄O₁₀ and SO₃

• Simple molecular

Why does SiO₂ have a high melting point

• Has a giant covalent structure

• Strong covalent bonds between atoms

• A lot of energy is required to overcome these bonds

Why do simple molecular substances tend to have low MPs

• Weak IM forces between molecules

• Very little energy needed to overcome VDWS forces between molecules

• (VDWS forces increase with size of molecule therefore P₄O₁₀ has a higher MP than SO₃)

Explain why Na₂O has a higher MP than SO₃

• It exists as a giant ionic lattice with strong ionic bonding

• SO3 is simple molecular

• Electrostatic forces of attraction between Na+ and O^2- in lattice are much stronger than VDWS forces between SO3 molecules

What do the reactions of P3 oxides with water depend on

• The type of bonding

Ionic oxide examples and how they react with water

• Na₂O and MgO

• Contain oxide ions which react with water to produce OH ions

• Forming alkaline solutions

Insoluble oxides examples and how they react with water

• Al₂O₃ and SiO₂

• Little to no reaction with water

Examples of molecular oxides and how they react with water

• P₄O₁₀ and SO₂ and SO₃

• Form acidic solutions with water

Equations for both Na₂O and MgO reacting with water

• Na₂O + H₂O → 2NaOH

• MgO + H₂O → Mg(OH)₂

Why is NaOH solution more alkaline than Mg(OH)₂

• Sodium hydroxide is more soluble (i.e dissociates more)

• [OH^-] is greater

• Ph is higher

Equations of how the 3 non-metal oxides react with water

• SO₂ + H₂O → H₂SO₃ / Weak acid

• SO₃ + H₂O → H₂SO₄ / Strong acid

• P₄O₁₀ + 6H₂O → 4H₃PO₄ / Weaker than sulfuric acid stronger than H2SO3

Structure of H₂SO₃ and its anion

Structure of H₂SO₄ and its anion

Structure of H₃PO₄ and its anion

What will happen to the Ph of water when Al₂O₃ or SiO₂ is added

• Will stay 7

Why is SiO₂ insoluble

• Has strong covalent bonds between atoms

• H2O cannot supply enough energy to break the strong covalent bonds

Why is Al₂O₃ insoluble

• Is an Ionic oxide

• Al3+ has a very high charge density

• Leads to additional covalent character

• Therefore very strong attractions within the lattice that H2O cant overcome

3 tests to distinguish between aq solutions of sulfur trioxide and sulfur dioxide

List basic oxides and acidic oxides

Basic- React with acids

• Na₂O

• MgO

Acidic-React with bases

• SiO₂

• P₄O₁₀

• SO₃

• SO₂

What is special about Al₂O₃

• It is amphoteric

• Meaning it reacts with acids and bases

Equation of Nitric acid reacting with MgO

Equation of Phosphoric acid reacting with Na₂O

Equation of Phosphoric acid reacting with MgO

Equation for SO₃ reacting with KOH

Equation of P₄O₁₀ reacting with NaOH

Equation for Al₂O₃ reacting with HCL and H₂SO₄ (acids)

Equation for Al₂O₃ reacting with NaOH (base)

General equation for P3 oxides reacting with each other

• Acid + Base → Salt

• No water

Equation for P₄O₁₀ reacting with MgO

Equation for SO₃ reacting with Al₂O₃

• P₄O₁₀ + 6MgO → 2Mg₃(PO4)₂

• 3SO₃ + Al₂O₃ → Al2(SO4)₃