Group 2

Question 1

What is the reaction between Mg and oxygen?

Answer 1

2Mg (s) + O2 (g) —–> 2MgO (s)
-burns easily
-bright white flame

Question 2

What is the reaction between Mg and water?

Answer 2

Mg (s) + H2O (l) ——> Mg(OH)2 (s) + H2 (g)
-vigorous reaction with steam
-very slow reaction with water

Question 3

What is the reaction between Ca and oxygen?

Answer 3

2Ca (s) + O2 (g) ——> 2CaO (s)
-difficult to ignite
-red flame

Question 4

What is the reaction between Ca and water?

Answer 4

Ca (s) + O2 (g) ——> Ca(OH)2 (s) + H2 (g)
- reacts moderately
- hydroxide formed

Question 5

What is the reaction between Sr and oxygen?

Answer 5

2Sr (s) + O2 (g) ——> 2SrO (s)
Sr (s) + O2 (g) ——> SrO2 (s)
-difficult to ignite
-red flame

Question 6

What is the reaction between Sr and water?

Answer 6

Sr (s) + 2H2O (l) → Sr(OH)2 (aq) + H2 (g)
-reacts rapidly
-hydroxide produced

Question 7

What is the reaction between Ba and oxygen?

Answer 7

2Ba (s) + O2 (g) → 2BaO (s)
Ba (s) + O2 (g) → BaO2 (s)
-difficult to ignite
-green flame

Question 8

What is the reaction between Ba and water?

Answer 8

Ba (s) + 2H2O (l) → Ba(OH)2 (aq) + H2 (g)
-reacts vigorously
-hydroxide formed

Question 9

What is the reaction between Ba and dilute HCl?

Answer 9

Ba (s) + 2HCl (aq) → BaCl2 (aq) + H2 (g)
-reacts vigorously

Question 10

What is the reaction between Ba and dilute H2SO4?

Answer 10

Ba (s) + H2SO4 (aq) → BaSO4 (s) + H2 (g)
-reaction is quickly stopped by the formation of an insoluble sulfate layer on the metal surface

Question 11

What is the reaction between Sr and dilute H2SO4?

Answer 11

Sr (s) + H2SO4 (aq) → SrSO4 (s) + H2 (g)
-reaction is quickly stopped by the formation of an insoluble sulfate layer on the metal surface

Question 12

What is the reaction between Sr and dilute HCl?

Answer 12

Sr (s) + 2HCl (aq) → SrCl2 (aq) + H2 (g)
-reacts vigorously

Question 13

What is the reaction between Ca and dilute HCl?

Answer 13

Ca (s) + 2HCl (aq) → CaCl2 (aq) + H2 (g)
-reacts vigorously

Question 14

What is the reaction between Ca and dilute H2SO4?

Answer 14

Ca (s) + H2SO4 (aq) → CaSO4 (s) + H2 (g)
-reaction is slowed by the formation of a sparingly soluble sulfate layer which coats the metal surface stopping hydrogen bubbles from rising

Question 15

What is the reaction between Mg and dilute H2SO4?

Answer 15

Mg (s) + H2SO4 (aq) → MgSO4 (aq) + H2 (g)
-reacts vigorously

Question 16

What is the reaction between Mg and dilute HCl?

Answer 16

Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g)
-reacts vigorously

Question 17

All group 2 oxides basic?

Answer 17

yes all except BeO which is amphoteric

Question 18

What is thermo decomposition?

Answer 18

the breakdown of a compound into two or more different substances using heat

Question 19

When do group 2 carbonates break down (decompose)

Answer 19

when they are heated to form the metal oxide and give off carbon dioxide gas

Question 20

What does thermal stability do when going down the group

Answer 20

increases
-The smaller positive ions at the top of the groups will polarise the anions more than the larger ions at the bottom of the group
The small positive ion attracts the delocalised electrons in the carbonate ion towards itself
The higher the charge and the smaller the ion the higher the polarising power

-The more polarised they are, the more likely they are to thermally decompose as the bonds in the carbonate and nitrate ions become weaker

Question 21

What does melting point do going down the group

Answer 21

decreases
-the ionic radius of the metal ion increases

-This results in a weaker electrostatic attraction between the delocalised electrons and the positive nuclei

Question 22

What does first ionisation energy do going down the group

Answer 22

decreases
-The atomic radius and shielding effects down groups are greater than the nuclear charge effect, leading to an overall decrease in ionisation energies as you move down group 2.

Question 23

Does reactivity increase going down group 2? Explain

Answer 23

yes it does
-Since it becomes easier to remove electrons further down the group, the reactivity of group 2 metals increases