Group 2 - Alkaline Earth Metals

Question 1

What happens to the atomic radius down group 2 and why?

Answer 1

The atomic radius increases because there are more electron shells.

Question 2

What happens to the 1st ionisation energy down group 2 and why?

Answer 2

The 1st ionisation energy decreases because the atoms get bigger and there’s more electron shielding, therefore there is a weaker attraction between the nucleus and the outer shell electron.

Question 3

What happens to the melting point down group 2 and why?

Answer 3

The melting point decreases because there is weaker metallic bonding due to metal ions getting bigger.

Question 4

Which element is the exception to the trend of melting points down group 2?

Answer 4

Magnesium.

Question 5

Barium reacts with water. What can be observed?

Answer 5

It will fizz in water and form a colourless solution.

Question 6

Barium reacts with water. What is the equation for this reaction?

Answer 6

Ba (s) + 2H2O (l) –> Ba(OH)2 (aq) + H2 (g)

Question 7

Strontium reacts with water. What can be observed?

Answer 7

It will fizz in water and form a colourless solution.

Question 8

Strontium reacts with water. What is the equation for this reaction?

Answer 8

Sr (s) + 2H2O (l) –> Sr(OH)2 (aq) + H2 (g)

Question 9

Calcium reacts with water. What can be observed?

Answer 9

It will fizz in water and after a time, a white solid forms (which is Ca(OH)2, which is slightly soluble in water).

Question 10

Calcium reacts with water. What is the equation for this reaction?

Answer 10

Ca (s) + 2H2O (l) –> Ca(OH)2 (aq) + H2 (g)

Question 11

Magnesium reacts with cold water. What can be observed?

Answer 11

A very slight reaction. Reaction soon stops because Mg(OH)2 is insoluble in water and forms a barrier preventing further reaction.

Question 12

Magnesium reacts with cold water. What is the equation?

Answer 12

Mg (s) + 2H2O (l) –> Mg(OH)2 (s) + H2 (g)

Question 13

Magnesium reacts with steam. What can be observed?

Answer 13

Burns with a white flame to form a white powder.

Question 14

Magnesium reacts with steam. What is the equation?

Answer 14

Mg (s) + H2O (g) –> MgO (s) + H2 (g)

Question 15

Is magnesium hydroxide soluble?

Answer 15

No.

Question 16

Is calcium hydroxide soluble?

Answer 16

Slightly.

Question 17

Is strontium hydroxide soluble?

Answer 17

Yes.

Question 18

Is barium hydroxide soluble?

Answer 18

Yes.

Question 19

Is magnesium sulfate soluble?

Answer 19

Yes.

Question 20

Is calcium sulfate soluble?

Answer 20

Yes.

Question 21

Is strontium sulfate soluble?

Answer 21

No.

Question 22

Is barium sulfate soluble?

Answer 22

No.

Question 23

How do you test for sulfate ions?

Answer 23

Add barium chloride (BaCl2) and dilute hydrochloric acid (HCl). If sulfate ions are present, a white precipitate will form. The hydrochloric acid is added to remove any other ions that could give a precipitate with barium chloride.

Question 24

What is the use of magnesium (not medicine!)?

Answer 24

To extract titanium from the ore TiO2 (rutile).

Question 25

What is titanium used for?

Answer 25

Replacement joints.

Question 26

What are the equations for the extraction of titanium?

Answer 26

TiO2 + 2C + 2Cl2 –> TiCl4 + 2CO

TiCl4 + 2Mg –> Ti + 2MgCl2

Question 27

What is a use of magnesium in medicine?

Answer 27

Mg(OH)2 is used to treat indigestion.

Question 28

What is a use of calcium hydroxide?

Answer 28

Ca(OH)2 is a slaked lime put on fields to make soil less acidic.

Question 29

What is a use of calcium oxide?

Answer 29

Flue gas desulfurisation.

CaO + SO2 –> CaSO3

Question 30

What is a use of barium?

Answer 30

In medicine: a drink of BaSO4 before an x-ray/scan allows blockages to be seen.