Year 12 - Group 2 - The alkaline Earth metals Flashcards
What happens to the atomic radius as you go down group 2?
It increases due to more shells being added.
What happens to the first ionisation energy as you go down group 2?
It decreases due to increased shielding meaning that the electrons are further away from the nucleus meaning that the electrostatic forces are weaker and therefore less energy is needed to remove an electron.
Describe the trend in melting points as you go down group 2.
In general the melting points decrease as a result of the metal ions increasing as you go down the group however the number of delocalised electrons stays the same (2) therefore the larger the ionic radius the further away the delocalised electrons are from the positive nuclei, meaning that it takes less energy to break the bonds.
In terms of melting points, why is magnesium different , with its melting point being lower than the others?
This is due to a change in the crystal structure (the arrangement of the metallic ions).
State the products made when group 2 metals react with water.
A metal hydroxide and hydrogen are produced.
State the trend in solubility in compounds which contain singly charged negative ions. (e.g. OH-)
Generally their solubility increases as you go down the group.
State the trend in solubility in compounds which contain doubly charged negative ions. (e.g. S04, 2- (sulfate ion))
Generally solubility decreases down the group.
How and why is Barium sulfate able to be used during a ‘barium meal’.
Barium sulfate is insoluble and therefore can be drank by a patient and will appear on an X-ray. It can be used to help diagnose problems with the oesophagus, stomach or intestines. A suspension of barium sulfate is used however other barium compounds couldn’t be used as they’re poisonous.
How can magnesium be used to help extract titanium from its ore?
The main titanium ore (titanium oxide, TiO2) is first converted to titanium chloride (TiCl4) by heating it with carbon in a stream of chloride gas. The titanium chloride is then purified by fractional distillation, before being reduced by magnesium in a furnace at almost 1000degreesC.
How is sulfur dioxide removed from flue gases?
Calcium oxide (CaO) and calcium carbonate (CaCO3) can both be used in a process known as wet scrubbing (reacting flue gases with an alkali). A slurry is made by mixing either of these with water and it is then sprayed onto the flue gases. The sulfur dioxide reacts with the alkaline slurry and produces a solid waste product. calcium sulphite.
What are many of the common alkaline earth metal compounds used for?
They are used for neutralising acids. For example calcium hydroxide - Ca(OH)2 - is used in agriculture to neutralise acidic soil and magnesium hydroxide, (Mg(OH)2, is used in some indigestion tablets as an antacid.
