chapter 9- group 2- the alkaline earth metals Flashcards
(17 cards)
why are group 2 elements called the alkaline earth metals
because their oxides and hydroxides are alkaline
what happens to the metallic/ atomic radius of group 2 elements going down the group
it increases
what happens to the first and second ionisation energy of group 2 elements going down the group
decreases down the group
what happens to the density of group 2 elements going down the group
it increases
what happens to the melting points going down the group 2 elements
it decreases as the strength of the metallic bond decreases down the group
what is the only anomaly in the trend of melting points of group 2 elements
magnesium, which has the lowest melting point
what happens to the reactivity of group 2 metals and water going down a group
the metals get more reactive going down the group
what is the reaction equation for any group 2 metal and water
M (s) + 2H2O (l) ——- M(OH)2 (aq) + H2 (g)
what is one use of magnesium hydroxide
used in indigestion remedies to neutralize excess stomach acid which causes heartburn and indigestion
what is one use of calcium hydroxide and another name given to it
name: slaked lime
and is used to treat acidic soil
what happens to the solubility of group 2 hydroxides going down the group
- going down the group they become more soluble
what does barium hydroxide dissolve into
a strong alkaline solution
what happens to the solubility of the group 2 sulfates going down the group
they become less soluble going down the group
what is one use of barium sulfate and why it is used in that way
it is used as a barium meal to outline the gut in medical- X-rays since the heavy barium atom is very good at absorbing X-rays and is so insoluble that the test is safe
what is the steps in a simple test for sulfate ions in solution using barium sulfate
- the solution is first acidified with nitric of hydrochloric acid
- then barium chloride solution is added to the solution under test
- if a sulfate is present a white precipitate of barium sulfate is formed
why is an acid used at the beginning of the test for sulphate ions in solution using barium sulfate
to remove carbonate ions as carbon dioxide, due to barium carbonate also being a white insoluble solid which would make it indistinguishable from barium sulphate
what is the reaction equation for the barium sulfate test for sulfate ions in solution
Ba 2+ (aq) + SO4 2- (aq) ——- BaSO4 (s)
