Unit 3.2.6 - Group 2

Question 1

Name four of the group 2 metals?

Answer 1

Magnesium, calcium, strontium and barium

Question 2

The group 2 metals are also called the?

Answer 2

Alkaline earth metals

Question 3

State the trend in atomic radius of the group 2 metals?

Answer 3

Increases as you go down the group

Question 4

Why does the atomic radius increase as you go down group 2?

Answer 4

There are more electron shells meaning the atom is larger and has a bigger atomic radius

Question 5

State the trend in the first ionisation energy of the group 2 metals?

Answer 5

Decreases as you go down the group

Question 6

Why does the first ionisation energy decrease as you go down group 2?

Answer 6

There are more electron shells which means a bigger atomic radius and more shielding, this means the outer electrons will be less strongly attracted to the nucleus and therefore easier to remove

Question 7

Does the reactivity increase or decrease as you go down group 2?

Answer 7

Increase

Question 8

State the general pattern in melting point of the group 2 metals?

Answer 8

Generally decreases as you go down the drop

Question 9

Why does the melting point of the group 2 metals generally decrease as you go down the group?

Answer 9

They have a typical metallic structure, and as you go down the group the size od the positive ion increases however the number of delocalised electrons stays the same. This means the delocalised electrons are further away from the positive ion reducing the strength of the metallic bonds, meaning they require less energy to overcome and so decreasing the melting point

Question 10

Between which two elements does the melting point not increases in the group 2 metals and why?

Answer 10

Between magnesium and calcium because the crystal structure of the metal ion changes

Question 11

What do group 2 metals react with water to give?

Answer 11

Metal hydroxide and hydorgen

Question 12

What is the equation for the reaction between a group 2 metal and water?

Answer 12

M + 2H20 ———-> M(OH)2 + H2

Question 13

What two negative ions when bonded with a group 2 metals do you have to know the solubility of ?

Answer 13

Hydroxides and sulphates

Question 14

State the trend in the solubility of metal hydroxides in the group 2 metals?

Answer 14

More soluble as you go down the group

Question 15

State the trend in the solubility of metal sulphates in the group 2 metals?

Answer 15

Less soluble as you do the group

Question 16

Is magnesium hydroxide or sulphate more soluble?

Answer 16

Sulphate

Question 17

Is barium hydroxide or sulphate more soluble?

Answer 17

Hydroxide

Question 18

What is another name for magnesium hydroxide and what is one of its uses?

Answer 18

Milk of magnesia - indigestion tablets

Question 19

What is another name for calcium hydroxide and what is one of its uses?

Answer 19

Slaked lime - neutralise acidic soil

Question 20

What is barium sulphate used for and why?

Answer 20

Used as a barium meal before an x ray, it is good at absorbing x rays so it helps to outline the gut in an x ray

Question 21

Why can barium be used as a barium meal even though barium ions are toxic?

Answer 21

Barium sulphate is insoluble so won’t dissolve in your body

Question 22

What test can you do for sulphate ions and what result would you expect?

Answer 22

Add acidified barium chloride to the solution, if sulphate ions are present a white precipitate of barium sulphate will form