10. Group 2

Question 1

Describe the trend for group 2 elements reacting with oxygen and the colors of the flames

Answer 1

Decreases as you go down the group
Mg- white flame
Ca- red flame
Sr- red flame
Ba- green flame

Question 2

Describe the trend for group 2 elements reacting with water

Answer 2

Increases down the group.

Question 3

Describe the trend for group 2 elements reacting with dilute HCl

Answer 3

They all react vigorously.

Question 4

What is observed when Ca is reacted with dilute sulfuric acid

Answer 4

The reaction is slowed by the formation of a sparingly soluble sulfate layer which coats the metal surface stopping hydrogen bugles from rising

Question 5

Describe what is observed when Sr reacts with dilute sulfuric acid

Answer 5

The reaction is stopped by the formation of an insoluble sulfate layer on the metal surface

Question 6

What is observed when Ba reacts with dilute sulfuric acid

Answer 6

The reaction is stopped by the formation of an insoluble sulfate layer on the metal surface

Question 7

Describe the trend of thermal stability down group 2

Answer 7

Increases down the group.
More energy is needed to break down the carbonate and nitrite ions

Question 8

Describe general reactivity of Group 2 elements

Answer 8

They become more reactive down the group
It becomes easier for the atoms to lose two electrons and become 2- ions.

Question 9

Describe the trend in melting point down group 2 elements and

Answer 9

It decreases going down the group as the outer electrons get further away from the nucleus, this means that the attraction between the nucleus and the bonding electrons decreases.
Increase in size of cations, which weakens the bonds

Question 10

Flame test color for calcium compounds

Answer 10

Brick red color

Question 11

Flame test color for strontium compounds

Answer 11

Scarlet red colour

Question 12

Flame test colour for barium compounds

Answer 12

Apple green color

Question 13

pH of magnesium hydroxide solution

Answer 13

10

Question 14

pH of calcium hydroxide

Answer 14

11

Question 15

Explain why going down the group it gets easier to remove the outer two electrons

Answer 15

Although the nuclear charge on the nucleus increases going down the group factors such as increased shielding effect and a larger distance between the outermost electrons and the nucleus outweigh the attraction of the higher nuclear charge.