Period 3

• What is the general reaction when a base is added?


  Add a Base → Salt + Water
• What is the equation for magnesium reacting with water?

  Mg + H2O → Mg(OH)2 + H2
• What is compound Y formed when magnesium reacts with water?


  Mg(OH)2
• What is the element that forms a less alkaline oxide when reacting with water?

  Magnesium (Mg)
• Why does magnesium have a lower energy bond compared to sodium?


  Because it has fewer electrons to lose
• What is the difference between the two equations provided for magnesium's reaction with water?


  The first shows magnesium forming a less alkaline oxide, while the second shows it forming a less alkaline compound
• Do most Period 3 Elements react readily with oxygen?


  Yes
• How do bonding and structure affect the melting points of Period 3 Elements?


  Bonding and structure influence the melting points
• What type of oxides do the metals Na and Mg form when they react with oxygen?


  Ionic oxides
• How do non-metals bond with oxygen compared to metals?


  Non-metals form covalent bonds, while metals form ionic bonds
• What type of bond do non-metals form with oxygen?


  A single bond
• What type of bond do metals form with oxygen?


  A double bond
• What is the nature of the solutions formed by ionic oxides of Na and Mg when they combine with oxygen?


  The solutions are basic alkaline
• How do the solutions of covalent oxides compare to those of magnesium hydroxide?


  The solutions are more acidic than magnesium hydroxide
• What is the equation for the reaction of Na2O with water?


  Na2O + H2O → 2NaOH
• Why does MgO form a less alkaline solution?


  Because it has a higher bond energy compared to other oxides
• What happens when valent oxides dissolve in water?


  They form alkaline solutions with hydroxide ions.
• What is the reaction equation for magnesium oxide dissolving in water?

  MgO(s) + H₂O(l) → Mg(OH)₂(aq)
• What is the pH range of magnesium hydroxide solutions?


  pH 9 - 10
• What pH do the simple covalent oxides of phosphorus and sulfur form in solution?


  They form acidic solutions with a pH of about 0 - 2.
• What is the dissociation reaction of phosphoric acid in solution?

  H₃PO₄(aq) → 3H⁺(aq) + PO₄³⁻(aq)
• What is the dissociation reaction of sulfurous acid in solution?

  H₂SO₃(aq) → 2H⁺(aq) + SO₃²⁻(aq)
• What is the dissociation reaction of sulfuric acid in solution?

  H₂SO₄(aq) → 2H⁺(aq) + SO₄²⁻(aq)
• How do acidic oxides behave in relation to bases?


  They neutralize bases.
• What is the reaction equation for sulfur trioxide neutralizing water?

  SO₃(g) + 2H₂O(l) → H₂SO₄(aq)
• What is the reaction equation for sulfur dioxide reacting with sodium hydroxide?


  SO₂(g) + 2NaOH(aq) → Na₂SO₃(aq) + H₂O(l)
• What is the behavior of amphoteric oxides in relation to acids and bases?


  They can neutralize both acids and bases.
• What is the reaction equation for tetraphosphorus decoxide with water?


  P₄O₁₀(s) + 6H₂O(l) → 4H₃PO₄(aq)
• What is the reaction equation for aluminum oxide with water?


  Al₂O₃(s) + 3H₂O(l) → 2Al(OH)₃(aq)
• Why is silicon dioxide insoluble in water?


  It has a giant covalent structure.
• What happens when silicon dioxide reacts with bases?


  It forms salts.
• What are the characteristics of acidic oxides?


  • Form acidic solutions when dissolved in water
  • Neutralize bases
  • Dissociate in solution to produce hydrogen ions
• What are the characteristics of amphoteric oxides?


  • Can neutralize both acids and bases
  • React with water to form hydroxides
  • Exhibit dual behavior in chemical reactions
• What are the characteristics of silicon dioxide?


  • Insoluble in water due to giant covalent structure
  • Can react with bases to form salts
  • Acts as both an acid and a base
• What is the definition of periodicity in the context of the periodic table?

  Periodicity is the regular, repeating pattern in properties of elements across periods of the periodic table.
• What is the trend in atomic radius across elements in Period 3?

  Atomic radius decreases across the period.
• Why does the atomic radius decrease across Period 3?

  Atomic number increases, leading to increased nuclear charge while shielding remains almost constant.
• What is the trend in first ionisation energy across elements in Period 3?

  There is a general increase in first ionisation energy across the period.
• Why does first ionisation energy increase across Period 3?

  Nuclear charge increases while shielding remains almost constant, resulting in greater attraction between the nucleus and outermost electrons.
• Which groups deviate from the general trend in ionisation energy across a period?

  Group 3 (Aluminium) and Group 6 (Sulphur) deviate from the trend.