Inorganic: Group 2

Question 1

Explain the trend in atomic radius down group 2

Answer 1

Increases as you go down the group
Because the number of electron shells increase as you go down the group

Question 2

Explain the trend in first ionisation energy as you go down group 2

Answer 2

Decreases as you go down the group
Because the number of electron shells increases
So there is more shielding and the outermost electron is more weakly attracted to the positive nucleus
So requires less energy to remove

Question 3

Why does it not matter that the number of protons also increases as you go down the group

Answer 3

Increase in shielding counteracts this

Question 4

explain the trend in melting points of the group 2 elements

Answer 4

group 2 elements form metallic structures containing positive ions in a sea of delocalised electrons

As you go down the group the size of the metal ion increases but the charge and number of delocalised electrons remains the same

Larger ions means the distance between the positive nucleus and the delocalised electrons is greater. This means the attraction between the +ve ions and the delocalised electrons is weaker so the electrostatic forces of attraction require less energy to overcome

Therefore melting points decrease as you go down group 2

Question 5

Give a general equation for the reaction of G2 metals with water

Answer 5

M+2H2O>M(OH)2 + H2

Question 6

What is produced when g2 metals react with water

Answer 6

Base and hydrogen gas

Question 7

What is the trend for reactivity of g2 metals with water and explain this trend

Answer 7

Increase in reactivity as you go down the group

aTOMS GET LARGER SO OUTERMOST ELECTRONS ARE FURTHER FROM THE NUCLEUS SO MORE WEAKLY ATTRACTED. THIS MEANS THEY ARE EASIER TO REMOVE SO ARE MORE REACTIVE

Question 8

Given the trend in reactivity, which g2 metal does not react with water

Answer 8

Berylium

Question 9

Compare Mg reacitons with H2O based on its temperature

Answer 9

Mg reacts slowly with cold water and more vigorously with steam
When Mg reacts with steam it produces MgO instead of Mg(OH)2

Question 10

What is the trend in solubulities of the group 2 hydroxides

Answer 10

Solubility increases as you go down the group

Question 11

What is the trend in solubulities of the group 2 sulphates

Answer 11

Decreases as you go down the group

Question 12

How do you test for sulfates

Answer 12

Add HCl to remove any carbonates that could give a false positive

Add Barium Chloride

barium SULFATE white ppt will form as BaSO4 is insoluble

Question 13

Describe the use of Calcium Hydroxide in agriculture

Answer 13

Used to neutralise acidic soils

Question 14

Describe the use of Magnesium Hydroxide in Medicine

Answer 14

Used to neutralise excess stomach acid

Question 15

How is calcium oxide or calcium carbonate good for combatting pollution

Answer 15

Used to remove sulfur dioxide from flue gases

Question 16

What is wet scrubbing

Answer 16

When CaO OR CaCO3 is sprayed onto acidic sulfur dioxide gas

Question 17

What are the products of wet scrubbing

Answer 17

Calcium sulfite, Water (+co2 sometimes)

Question 18

Explaun the use of Barium Sulfate in medcine

Answer 18

Barium Sulfate is dense
Barium sulfate is used in meals for people to receive GI scans and so problems in the soft tissue that would not normally show up on x-ray show up

Question 19

Why can people eat barium sulfate containing compounds given that barium containing compounds they are toxic

Answer 19

BaSO4 is insoluble so not absorbed into the bloodstream

Question 20

Describe how Magnesium is used to extract titanium from its ore

Answer 20

TiO2 converted into TiCl4 by heating with C and Cl2 gas

TiCl4 passed through fractional distillation column to increase purity

TiCl4 reduced with magnesium in 1000c furnace

Question 21

State the equation for the reduction of TiCl4 by Mg

Answer 21

TiCl4 + 2Mg > Ti + 2MgCl2