2.2 Group 2 Flashcards
Write an equation for the first ionisation energy of Mg.
Mg (g) -> Mg+ (g) + e-
Explain why the first ionisation energies of period 2 metals looks like it does.
*It is an overall increase as the proton number increases but number of shielding electrons stays constant
*It dips at Al and S - this is because the 3p1 electron in Al is in a higher energy level than 3s, and S experiences electron repulsion in a spin pair which makes its electron easier to lose.
What happens to the first ionisation energies as you go down group 2 ?
•It decreases
•This is because the atomic radius increases with each increment of the group, and additional protons are counteracted by additional electron shielding
•This means that there is a weaker electrostatic force holding the outer electron in place, meaning less energy is required to lose it.
How does reactivity with water change when you go down group 2 ?
•It increases
•This is because the outer electrons are lost more easily (additional shielding + atomic radius).
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 and steam.
Mg (s) + H2O (g) -> MgO (s) + H2 (g)
What is the trend in hydroxide solubility as you go down group 2 ?
•It 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 2
•MgSO4 is soluble
•BaSO4 is insoluble.
What is the trend in melting point down group 2 ?
•Decreases down the group
•This is because the sea of delocalised electrons is further from the positive charge of the nucleus
•This means there is weaker metallic / forces of attraction which means less energy is required to melt.
What is the trend in atomic radius down group 2 ?
It increases down the group as there are more occupied electron shells down the group.
Write the equations for the extraction or titanium using magnesium.
TiO2 + 2Cl2 -> TiCl4 + O2
TiCl4 + 2Mg -> Ti + 2MgCl2
What are flue gasses ?
Gases produced by power stations which are harmful to the environment.
How can CaO or CaCO3 be used to remove flue gasses ? Show 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.
•Its used to neutralise soil
•Ca(OH)2 + 2HCl -> 2H2O + CaCl2
What is Mg(OH)2 used for ?
Used to treat heartburn
