Group 2 Flashcards
Sulfur dioxide can be removed from waste gases in a power station by what reaction?
an acid-base reaction with calcium oxide
What are the elements of group II sometimes called?
the Alkali Earth metals
What block are group II elements in?
s
Are group II or group I elements more reactive?
group I
What solution can be used to test for sulfate ions?
BaCl2 (barium chloride)
What is the observation when barium sulfate forms?
a white precipitate
What is the ionic equation for the formation of barium sulfate?
Ba2+ (aq) + SO4 2- (aq) -> BaSO4 (s)
Are group 2 elements good conductors of electricity and heat?
Yes
What is the trend in first ionisation energies as you go down group 2?
decreases
What is the general trend in atomic radius going down group 2?
increase because each element going down the group has an additional filled electron shell in comparison to the element above it
Do the elements in group 2 generally have high melting points?
Yes because they are all metals and therefore form metallic bonds and exist as giant metallic structures
What is the general trend in melting point down group 2?
going down group 2, the ions get bigger so the attraction between the ‘sea’ of delocalised electrons and metal ions is weaker and the metallic bonds are weaker so the melting point decreases going down the group
Which element in group 2 is an anomaly for the general trend in melting points going down group 2?
Magnesium as it has the lowest melting point of group 2 (no straight forward reason)
What is the general trend for 1st and 2nd IEs going down group 2?
decrease because the outer most electrons are held increasingly further away and so less energy is needed to overcome the attraction between the nucleus and the outer 2 electrons
Are group 2 elements always oxidised or reduced when they take part in reactions?
oxidised
What is the general equation for the reaction of all group 2 elements (M) with liquid water?
M(s) + 2H2O(l) -> M(OH)2(aq) + H2(g)
What is the trend in reactivity as you go down group 2?
increases going down the group
What is the general trend in reactivity with water going down group 2?
the reactions with water become more violent going down the group
What is magnesium hydroxide also called and what is it used for?
‘milk of magnesia’ and is used as an indigestion remedy to neutralise stomach acid
How fast does Mg react with cold water?
very slowly
Does Mg react more or less vigorously with steam than liquid water?
more vigorously with steam
What is the equation for the reaction of Mg with steam?
Mg(s) + H2O(g) -> MgO(s) + H2(g)
What does the reaction of magnesium with steam produce?
magnesium oxide and hydrogen gas
What is the general trend for the reactions with steam going down group 2?
similar to magnesium but they are also increasingly more vigorous as you go down the group
What is the general formula for group 2 (M) hydroxides?
M(OH)2
What is the general formula for group 2 (M) sulfates?
MSO4
What is the general trend of the solubility of group 2 hydroxides going down group 2?
solubility increases going down group 2
What is the general trend of the solubility of group 2 sulfates going down group 2?
solubility decreases going down group 2
What are substances with a low solubility called?
sparingly soluble
What is a use of barium sulfate?
x-ray imaging of internal organs and soft tissue
Why is barium sulfate used in x-ray imaging?
barium sulfate is very good at absorbing x rays
How is barium sulfate used in x ray imaging?
- the digestive system can be imaged using x-rays by feeding the patient a ‘barium meal’ (which consists of a paste made of barium sulfate)
- the paste fills the digestive system and then when an x-ray is taken the x-rays are absorbed and an image of the organs can be obtained
If barium sulfate is highly toxic, how come it is perfectly safe to feed to patients?
because it is so insoluble it cannot dissolve and pass through cell membranes into body tissue
Are group 2 metals good conductors of electricity?
Yes they are better than group 1 metals
What are the observations when barium metal is added to an excess of water?
forms a colourless solution and effervesces
