2.2 Group 2 Metals Flashcards
Write an equation for the first ionisation energy of magnesium
Mg (g) —> Mg+ + e-
Explain why this graph is this shape
First ionisation energy increases across group 3 because of increased nuclear charge, decreased atomic radius and same electron shielding means more energy needs to remove the first electron
Dips at Al because: outer electron is in a 3p orbital, higher energy than 3s orbital —> less energy needed to remove electron
Dips at S because one 3p orbital contains two electrons —> repulsion between paired electrons—> less energy needed to remove one
What happens to the first ionisation energy as you go down group 2? Why?
Decreases because :number of filled electron shells increases down the group —> increased shielding, increases atomic radius —> weaker force between outer electron and nucleus—> less energy needed to remove electrons
How does reactivity with water change as you go down group 2 and why?
Increases (Mg least —> Ba most)
Because outer electrons further from nucleus and more electron shielding, so 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)
Write an equation for the reaction of magnesium and steam
Mg(s) + H2O (g) —> MgO (s) + H2 (g)
What is the trend in hydroxide solubility down group 2?
Increases down the group
Mg(OH)2 is almost insoluble
Ba(OH)2 creates a strong alkaline solution
What is the trend in sulphate solubility down group 2?
Decreases down group
MgSO4 is soluble
BaSO4 is insoluble
What is the trend in melting point down group 2? Why?
Decreases down group
Because sea of delocaslises electrons is further from the positive charge of the nucleus—> weaker metallic bonds / forces of attraction which take less energy to overcome
What is the trend in atomic radius down group 2
Increases as there are more occupied electron shells down the group
Write the equations for the extraction of titanium using magnesium
TiO2 + 2Cl2 + C —> TiCl4 + CO2
TiCl4 (l) + 2Mg (S) —> 2MgCl2 (s) + Ti (S)
What are flue gases
Gases produced by power stations which are harmful for the environment
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)
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)
What is Mg(OH)2 used for?
Milk of magnesia - antacid to treat indigestion, heartburn, wind etc
