3.2.2 Group 2, the alkaline earth metals

Question 1

Atomic radius ____ down group 2 ?

Answer 1

Increases due to extra electrons and therefore shells

Question 2

Ionisation energy ____ down group 2 and why ?

Answer 2

Decreases, due to more shielding and therefore a weaker attraction between nucleus and outer shell electrons making them easier to remove

Question 3

Melting points generally ____ down the group and why ?

Answer 3

Decrease, as larger ions mean that the distance between the positive nuclei and delocalised electrons is greater which weakens the attractive force

Question 4

What type of bonding is present in group 2 and what does this mean ?

Answer 4

Metallic bonding, positive metal ions attracted to a negative delocalised sea of electrons

Question 5

Does reactivity increase or decrease down the group ?

Answer 5

Reactivity increases down the group as there is more shielding

Question 6

Do group 2 metals act as acids or bases ?

Answer 6

Bases, they are alkaline metals

Question 7

When group 2 metals react with water, what do they form ?

Answer 7

Metal hydroxides. e.g Mg(OH)2

Question 8

Group 2 sulphates and hydroxides have ____ solubility as we go down the group

Answer 8

Opposite

Question 9

Generally if the negative ion has a double charge they become _____ soluble down the group e.g SO4^2-

Answer 9

Less

Question 10

Generally if a negative ion has a single charge they become _____ soluble down the group e.g OH-

Answer 10

More

Question 11

What solution is used to test for sulphates ?

Answer 11

Barium chloride

Question 12

Why must HCl be added before barium chloride ?

Answer 12

In order to remove any carbonate ions that may give a false positive

Question 13

What is the positive result for a sulphate test with barium chloride ?

Answer 13

White precipitate will be formed, the precipitate is barium sulphate and is insoluble

Question 14

What group 2 metal is used for medical reasons and what does it do ?

Answer 14

Mg(OH)2, it is used to neutralise stomach acids

Question 15

What is the ionic equation for neutralisation ?

Answer 15

H+(aq) + OH-(aq) —-> H2O(l)

Question 16

What is a barium meal and what is it used for ?

Answer 16

Barium sulfate, it is used to identify problems in the digestive tract as it coats the stomach lining (soft tissues) and shows up on an x-ray

Question 17

What are the problems with barium compounds and why are barium meals an exception ?

Answer 17

Barium compounds are toxic but can be used in the body as barium sulfate is insoluble and therefore cannot be absorbed into the blood

Question 18

What is the equation for the extraction of titanium from its ore ?

Answer 18

TiCl4 + 2Mg —-> Ti + MgCl2

Question 19

Why is magnesium used in the extraction of titanium ?

Answer 19

As it acts as a reducing agent

Question 20

What is calcium hydroxide commonly used for ?

Answer 20

It is used to neutralise acidic soils in agriculture

Question 21

What is wet scrubbing ?

Answer 21

The process of removing sulfur dioxide by reacting it with an alkali such as CaO or CaCO3 (mixed with water)

Question 22

Give an equation to show how CaO can be used to react with sulfur dioxide

Answer 22

CaO(s) + 2H2O(l) + SO2(g) —-> CaSO3(aq) + 2H2O(l)