group 2 Flashcards
first ionisation energy of Mg
Mg (g) –> Mg+ (g) + e-
first ionisation graph generally increases but has 2 dips. where and why
generally increases = increased nuclear charge, decreased atomic radius and same electron shielding means more energy is needs to remove the first electron
dips at Al = outer electron is 3p orbital, higher energy than 3s orbital = less energy needed to remove first electron
dips at S = one 3p orbital contains 2 electrons = repulsion between paired electrons = less energy needed to remove one
what happens to the first ionisation energy as you go down group 2
decreases
number of 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 (Mg least, Ba most)
outer electrons further from nucleus and more electron shielding, so electrons are lost more easily
write an equation for the reaction of Ba and water
Ba (s) + 2H2O (l) –> Ba(OH)2 (aq) + H2 (g)
equation for Mg 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
decreases down group
sea of delocalised electrons is further from the positive charge of the nucleus = weaker metallic bonds / forces of attraction which takes 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
equations for extraction of Ti and Mg
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 to the environment
how can CaO be used to remove flue gases
CaO (s) + SO2 (g) –> CaSO3 (s)
how can CaCO3 be used to remove flue gases
CaCO3 (s) + SO2 (g) –> CaSO3 (s) + CO2 (g)
what is Ca(OH)2 used for and equation
neutralise soil
Ca(OH)2 (aq) + 2HCl (aq) –> 2H2O (l) + CaCl2 (aq)
