Group 2

Question 1

What is the trend in melting points in group 2

Answer 1

Decreases

Question 2

Why does melting point decrease as you go down the group

Answer 2

Delocalised electrons further away from nucleus
Strength of metallic bonds decrease
So it’s easier to break them

Mg is built different

Question 3

What is the trend in solubility with hydroxides

Answer 3

It increases

Question 4

What is the use of Mg(OH)2

Answer 4

It is an antacid (indigestion tablets)

Question 5

What do we use magnesium hydroxide instead of barium hydroxide in antacids

Answer 5

Magnesium hydroxide is sparingly soluble, therefore it won’t affect the ph of the stomach, but barium hydroxide would

Question 6

What is the trend of solubilities in group two with sulfates

Answer 6

It decrease

Question 7

What is the barium sulfate used for

Answer 7

Barium meal is used in X-Rays so we can see the digestive tract properly. Barium is a large atom so it can absorb the x-rays

Question 8

Barium sulfate is toxic, so why do we use it in X-Rays

Answer 8

Barium sulfate is insoluble, so it will pass through and it won’t be absorbed by the body

Question 9

What is the use of calcium hydroxide

Answer 9

It use as slaked lime which neutralises the acidic soils. It is cheap to use

Question 10

Write a general reaction for group two metals and steam

Answer 10

M + H20(g) -> M0 +H2

M being group 2 metal

Question 11

Write a general equation for the reaction with group two and water

Answer 11

M + H20(l) -> M(OH)2 + H2

M being a group 2 metal

Question 12

What is the full electron configuration of Calcium

Answer 12

1s2, 2s2, 2p6, 3s2, 4s2, 3p6

Question 13

State and explain the trend in the first ionisation energies of the elements in Group 2 from magnesium to barium.

Exam question

Answer 13

1. decreases

why?
1. shielding increases, as does atomic radius this means that less energy is required to remove electrons

Question 14

What is another use of barium that’s not in imaging

Answer 14

Barium chloride can be a test for sulfates

Question 15

How can you test for sulfates

Answer 15

Add HCL and add barium chloride

If positive a white ppt will form

Question 16

What is a positive result for sulfates

Answer 16

A white precipitate

Question 17

Why do we had HCL then barium chloride

Answer 17

To remove any carbonates which could give us a false positive

Question 18

What is the trend reactivity in group 2

Answer 18

It increases

Question 19

Solutions of barium hydroxide are used in the titration of weak acids.

State why magnesium hydroxide solution could not be used for this purpose.

Exam question

Answer 19

Magnesium hydroxide is insoluble

Question 20

Give the formula of a Group 2 metal hydroxide used in agriculture.

Exam question

Answer 20

Ca(OH)2

Question 21

Give the formula of the least soluble hydroxide of the Group 2 metals from Mg to Ba

Exam question

Answer 21

Mg(OH)2

Question 22

Explain why calcium has a higher melting point than strontium.

Answer 22

In calcium delocalised electrons closer to positive nucleus

Or cations are smaller

For mark 2

Ça has a stronger attraction from the positive metal ions to the delocalised electrons

Question 23

Acidified barium chloride solution is used as a reagent to test for sulfate ions.

State why sulfuric acid should not be used to acidify the barium chloride.

Exam question

Answer 23

Contains sulfate ions

Or

Will form a white precipitate