Group 2 metals Flashcards
write an equation for the first ionisation energy of magnesium.
Mg(g) ——-> Mg+ (g) + e-
Explain the trends in first ionisation energy along period 3
increases along period 3 because of increased nuclear charge, decreased atomic radius and same electron shielding means more enrgy is needed to remove the first outer electron.
Dips at Al: outer electron is in 3p orbital, higher energy than 3s orbital (further from nucleus=less attraction) so less energy is needed to remove an electron.
Dips at S: One 3p orbital contains two electrons, electron pair repulsion takes place, making it easier to remove an electron from outer shell.
What happens to the first ionisation energy as you go down group 2?
Decreases
number of filled electron shells increases down the group, this increases the shielding and atomic radius. Theres weaker attraction between the nucleus and outer shell electrons. Therefore, less energy is needed to remove an electron.
How does reactivity with water change as you go down group 2?
Increases (Mg=least, Ba=most)
outer shell electrons are further from the nucleus and has more electron shielding, so electrons are lost more easily.
Write an equation for the reaction of barium with water.
Ba (s) + 2H2O (l) ——-> Ba(OH)2 (aq) + H2 (g)
Write an equation for the reaction of magnesium with steam
Mg (s) + H2O (g) ——–> MgO (s) + H2 (g)
What is the trend in hydroxide solubility as you go down group 2?
Increases
Mg(OH)2 is almost insoluble
Ba(OH)2 creates a strong alkaline solution
What is the trend in sulphate solubility as you go down group 2?
Decreases
MgSO4 is soluble
BaSO4 is insoluble
What is the trend in melting point down group 2 and why?
Decreases
sea of delocalised electrons is further from the positive charge of the nucleus, weaker metallic bonds/forces of attraction means less energy is needed to break/overcome them.
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 extractions of TI using Mg
TiO2 + 2 Cl2 + C ——-> TiCl4 + CO2
TiCl4 (l) + 2Mg (s) ——-> 2MgCl2 (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? (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 e.t.c.
