2.2 Group 2 metals Flashcards
Write an equation for the first ionisation energy of magnesium
Mg(g) –> Mg+ (g) + e-
Why does first ionisation energy increase across period 3
Because of nuclear charge, decreased atomic radius and same electron shielding means more energy is needed 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 to remove one
What happens to first ionisation energy as you go down group 2, why?
Decreases because number if filled electron shells increases down the group –> increased shielding, increased atomic radius –> weaker force between outer electron and nucleus –> less energy needed to remove electron
How does reactivity with water change as you go down group 2
Increases
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 –> 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 the group
MgSO4 is soluble
BaSO4 is insoluble
What is the trend in melting point down group 2 why
Decreases down group
Because sea of positive delocalised electrons is further from the positive charge of the nucleus –> weaker metallic bonds/FOA which take 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
Write the equations for the
extraction of titanium using magnesium
TiO2 + 2Cl2 + C –> TiCl4 + C)2
TiCl4 (l) + 2Mg (s) –> “MgCl2 (s) + Ti (s)
What are flue gases
Gases produced by power stations which are harmful to the environment
How can CaO or CaCO3 be used to remove flue gases, write equationa
CaCO3 (s) + SO” (g) –> CaSO3 (s) + CO2 (g)
CaO (s) + SO2 (g) –> CaSO3 (s)
What is Ca(OH)2 used for
Write an equation for 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
