Group 2 Flashcards
What is the general trend of the atomic radius of group 2 going down the group?
-more electron shells
-so bigger atoms
What is the general trend of 1st ionisation energy of group 2?
-atoms get bigger
-more shielding
-therefore weaker attraction from nucleus to electron in outer shell
What is the general trend of the melting point of group 2 going down the group?
-weaker metallic bonding
-as metal ions are bigger
-lower charge density
-weaker FoA between ions and delocalised electrons
-so lower melting points
What can we observe in the reaction between Mg and steam ?And what is the equation?
-no reaction(or very slow) with cold water
-burns with white flame to form white powder with steam
-Mg+H20–>MgO + H2
What can we observe in the reaction between Ca and water?And what is the equation?
-fizzing
-floats to the top
-white solid
-Ca+2H2O—>Ca(OH)2+H2
What can we observe in the reaction between Sr and water?And what is the equation?
-more fizzing
-less white solid
-Sr+2H2O—>Sr(OH)2+H2
What can we observe in the reaction between Ba and water?And what is the equation?
-even more fizzing
-very soluble
-Ba metal disappears(no white solid)
-Ba+2H2O—>Ba(OH)2+H2
What is the trend in reactivity of group 2?
Becomes more reactive down the group
Can you explain the trend in reactivity down group 2?
-when the metals react, they lose their outer shell electrons
-Down the group, atoms become bigger and there is more shielding
-Therefore there is a weaker attraction between the nucleus and the outer shell electrons and so the outer shell electrons are more easily lost
What is used to neutralise acidic soils?
calcium hydroxide Ca(OH)2 (aka slaked lime)
What is used to neutralise antacids?
magnesium hydroxide Mg(OH)2
what is the ionic equation for neutralisation?
H+ + OH- —> H2O
What is the trend in the solubility of group 2 hydroxides?
solubility increases going down the group
What is the trend in the solubility of group 2 sulfates?
solubility decreases going down the group
what is a use of barium sulfate and why is it used?
barium sulfate is virtually insoluble
as a result, it can be taken by mouth as a barium meal to outline the gut in medical x rays(the barium metal is very good at absorbing x rays)
the insolublility of barium sulfate is also used in what?
used in a simple test for sulfate ions in solution
the solution is first acidified with nitric or hydrochloric acid, then barium chloride solution is added to the solution that is being tested and if a sulfate is present, a white precipitate of barium sulfate is formed.
what does magnesium extract?
titanium from it’s ore
what ore does titanium come from?
rutile
how is magnesium used to extract titanium from rutile?
1.titanium ore is converted to titanium chloride by heating with carbon and chlorine gas
2.the titanium chloride produced in step 1 is passed through a fractional distillation column to increase the purity
3.the purified titanium chloride is reduced using magnesium at 1000 degrees celsius furnace
what is the equation for the extraction of titanium?
TiCl4 +2Mg —>Ti + 2MgCl2
What is titanium used for?
-it’s strong, low density and had a high melting point
-it is used in the aerospace industry
-used for making replacement hip joints
why does sulfur dioxide need to be removed?
electricity can be produced by burning fossil fuels like coal. this produces sulfur dioxide which is a pollutant and can cause acid rain
how are sulfur dioxide emissions removed?
-by using calcium carbonate and oxide to remove sulfur dioxide emissions.
What are the reactions between SO2 and CaO/CaCO3?
CaO + SO2 —>CaSO3
CaCO3 + SO2 —>CaSO3 + CO2
