Group 2 Flashcards
Write an equation for the first ionisation energy of magnesium
Mg (g) → Mg⁺ (g) + e⁻
Represents the energy required to remove the outermost electron from a gaseous magnesium atom.
What happens to the first ionisation energy as you go down group 2? Why?
Decreases because: * number of filled electron shells increases * increased shielding * increased atomic radius
Weaker force between outer electron and nucleus results in less energy needed to remove the electron.
How does reactivity with water change as you go down group 2?
Increases (Mg least → Ba most)
Outer electrons are further from the nucleus and more electron shielding means electrons are lost more easily.
Write an equation for the reaction of Barium and water
Ba (s) + 2H₂O (l) → Ba(OH)₂ (aq) + H₂ (g)
This reaction shows barium’s reactivity with water.
Write an equation for the reaction of Magnesium and steam.
Mg (s) + H₂O (g) → MgO (s) + H₂ (g)
This demonstrates magnesium’s reaction with steam.
What is the trend in hydroxide solubility down group 2?
Increases down the group
Mg(OH)₂ is almost insoluble while Ba(OH)₂ creates a strong alkaline solution.
What is the trend in sulphate solubility down group 2?
Decreases down group
MgSO₄ is soluble while BaSO₄ is insoluble.
What is the trend in melting point down group 2? Why?
Decreases down group because: * sea of delocalised electrons is further from nucleus * weaker metallic bonds
Weaker forces of attraction require less energy to weaken.
What is the trend in atomic radius down group 2?
Increases as there are more occupied electron shells down the group
More electron shells lead to a larger atomic radius.
Write the equations for the extraction of Titanium using Magnesium.
TiO₂ + 2Cl₂ + C → TiCl₄ + CO₂; TiCl₄ (l) + 2Mg (s) → 2MgCl₂ (s) + Ti (s)
These reactions illustrate the process of extracting titanium.
What are flue gases?
Gases produced by power stations which are harmful to the environment
Flue gases include pollutants like SO₂ and NOₓ.
How can CaO or CaCO₃ be used to remove flue gases? Write equations.
CaCO₃ (s) + SO₂ (g) → CaSO₃ (s) + CO₂ (g); CaO (s) + SO₂ (g) → CaSO₃ (s)
These reactions neutralize harmful gases in flue emissions.
What is Ca(OH)₂ used for? Write an equation related to one of its uses.
Used to neutralise soil; Ca(OH)₂ (aq) + 2HCl (aq) → 2H₂O (l) + CaCl₂ (aq)
This reaction demonstrates its application in agriculture.
What is Mg(OH)₂ used for?
Milk of magnesia - antacid to treat indigestion, heartburn, wind etc.
Commonly used in over-the-counter medications.
What is a use of BaSO₄? Why is this safe?
In barium meals to outline gut in X-rays; Ba²⁺ is toxic but barium sulphate is insoluble
Insolubility prevents barium from being absorbed in the body.
