Period 3 and their Oxides Flashcards
Trend in Melting Point
Increases up to silicon then decreases
Trend in Boiling Point
Increases up to aluminium then decreases
Trend in Atomic Radius
- Decreases
- Nuclear Charge increases
- Shielding stays the same
- Outer electrons are pulled closer to the positive nucleus due to stronger attraction
Trend in 1st Ionisation energy
- Generally increases
- Exception 1: Mg to Al (the electron being removed from Al is in a higher energy orbital that is further from the nuclues)
- Exception 2: P to S (repulsion between electron pair in orbital so its easier to remove)
- Nuclear charge increases, shielding stays the same
Trend in Bonding Type
- Na, Mg, Al: Metallic Bonding
- Silicon: Covalent Bonding (metalloid, giant covalent structure)
- P, S, Cl: Covalent Bonding (non metals, simple covalent structure)
What are all the reactions in Period 3 examples of?
Redox Reactions
Reaction of Sodium and Water and Observations
- 2Na(s) + 2H₂O(l) –> 2NaOH(aq) + H₂(g)
- Vigourous reaction
- Floats on water
- Fizzing
- Melting due to heat energy released
Is the solution formed from the reaction of sodium and water acidic or alkaline?
Strongly Alkaline (13-14)
Reaction of Magnesium and Water and Observations
- Mg(s) + 2H₂O(l) –> Mg(OH)₂(aq) + H₂(g)
- Very slow reaction
- A few H₂ gas bubbles form after a few days
Is the solution formed from the reaction of magnesium and water acidic or alkaline?
Less alkaline than sodium and water reaction (9-10)
Reaction of Magnesium and Steam and Observations
- Mg(s) + H₂O(g) –> MgO(s) + H₂(g)
- Much more vigourous
- MgO precipitate forms
Reaction of Sodium and Oxygen
- 2Na(s) + ½O₂(g) –> Na₂O(s)
- Very spontaneous reaction
- Yellow/Orange Flame
- White precipitate forms
Reaction of Magnesium and Oxygen
- 2Mg(s) + O₂(g) –> 2MgO(s)
- Very spontaneous reaction
- Bright White Flame
- White precipitate forms
Reaction of Aluminium and Oxygen
- 4Al(s) + 3O₂(g) –> 2Al₂O₃(s)
- Quite spontaneous reaction
- Bright White flame
- White precipitate forms
Reaction of Silicon and Oxygen
- Si(s) + O₂(g) –> SiO₂(s)
- Reacts when heated strongly
- Bright White Flame
- White Precipitate forms
Reactions of Phosphorus and Oxygen
- 4P(s) + 5O₂(g) –> P₄O₁₀(s)
- 4P(s) + 3O₂(g) –> 2P₂O₃(s)
- Red phosphorus needs to heated to react
- White phosphorus reacts spontaneously
- Yellow Flame
- White precipitate forms for both
Reaction of Sulfur and Oxygen
- S(s) + O₂(g) –> SO₂(g)
- Needs to be heated to react
- Blue flame
- Colourless gas (no precipitate)
Bonding in Period 3 Oxides
- Sodium Oxide (Na₂O) - Giant Ionic
- Magnesium Oxide (MgO) - Giant Ionic
- Aluminium Oxide (Al₂O₃) - Giant Ionic (with covalent character)
- Silicon Dioxide (SiO₂) - Giant Covalent
- Phosphorus Pentoxide - (P₄O₁₀) - Simple Covalent
- Sulfur Dioxide (SO₂) - Simple Covalent
- Sulfur Trioxide (SO₃) - Simple Covalent
Trend in Melting and Boiling Points of Period 3 OXIDES
- Increases from sodium dioxide to magnesium dioxides
- Decreases after that
- This is because of difference in intermolecular forces between the molecules due to difference in bonding
Reaction of Sodium Oxide and Water
- Na₂O(s) + H₂O(l) - 2Na⁺(aq) + 2OH-(aq)
- Ions present: Na⁺ and OH-
- Strongly alkaline (13-14) as oxide ions react with water to form OH- ions
Reaction of Magnesium Oxide and Water
- MgO(s) + H₂O(l) –> Mg(OH)₂
- Mg(OH)₂ ⇄ Mg²⁺(aq) + 2OH-(aq)
- Ions present: Mg²⁺ and OH-
- Somewhat alkaline (9-10) as oxide ions react with water to form OH- ions
Reaction of Aluminium Oxide and Water
- No reaction as Al₂O₃ is insoluble in water
- No ions present
- Neutral (7)
Reaction of Silicon Oxide and Water
- No reaction as SiO₂ is insoluble in water
- No ions present
- Neutral (7)
Reaction of Phosphorus(V) Oxide and Water
- P₄O₁₀(s) + 6H₂O(l) –> 4H₃PO₄(aq)
- 4H₃PO₄(aq) ⇄ H⁺(aq) + H₂PO₄-(aq)
- Ions present: H⁺ and H₂PO₄-
- Fairly strong acid (1-2)
Reaction of Sulfur Dioxide and Water
- SO₂(g) + H₂O(l) –> H₂SO₃(aq)
- H₂SO₃ ⇄ H⁺(aq) + HSO₃-(aq)
- Ions present: H⁺ and HSO₃-
- Weak Acid (2-3)
Reaction of Sulfur Trioxide and Water
- SO₂(g) + H₂O(l) –> H₂SO₄(aq)
- H₂SO₄(aq) ⇄ H⁺(aq) + HSO₄-(aq)
- Ions present: H⁺ and HSO₄-
- Strong Acid (0-1)
Reactions of Sodium and Magnesium Oxides with Acids
- Na₂O(s) + 2HCl(aq) –> 2NaCl(s) + H₂O(l)
- MgO + H₂SO₄ –> MgSO₄(aq) + H₂O(l)
- Will always form a salt + water
Aluminium Oxide + Acid
Al₂O₃(s) + 3H₂SO₄(aq) –> Al₂(SO₄)₃(aq) + 3H₂O(l)
Aluminium Oxide + Base
Al₂O₃(s) + 2NaOH(aq) –> 2NaAl(OH)₄(aq) + 3H₂O(l)
Silicon Oxide + Base
SiO₂(s) + 2NaOH(aq) –> Na₂SiO₃(aq) + H₂O(l)
Phosphorus(V) Oxide + Base
P₄O₁₀(s) + 12NaOH(aq) –> 4Na₃PO₄(aq) + 6H₂O
Sulfur Dioxide + Base
SO₂(g) + 2NaOH(aq) –> Na₂ SO₃(aq) + H₂O(l)
Sulfur Trioxide + Base
SO₃(g) + 2NaOH(aq) –> Na₂SO₄(aq) + H₂O(l)
