inorganic 1 - group 2

Question 1

What is the trend in atomic radius down group 2?

Answer 1

A general increase.

Question 2

Why is there an increase in atomic radius down group 2?

Answer 2

Down the group the atomic radius gets bigger as there are more electron shells.

Question 3

What is the trend in first ionisation energy down group 2?

Answer 3

A general decrease.

Question 4

Why is there a general decrease in first ionisation energy down group 2?

Answer 4

Down group 2, the atomic radius gets bigger. Therefore the attraction between the positive nucleus and outer shell electron decreases down the group. Also, there is more shielding down the group and so an electron is lost more easily.

Question 5

What is the trend in electronegativity down period 2?

Answer 5

There is a general decrease.

Question 6

Why does electronegativity decrease down group 2?

Answer 6

Down group 2, the atomic radius increases and there is more shielding. Therefore, the attraction between the nucleus and two electrons in a covalent bond decreases. Therefore electronegativity decreases.

Question 7

What is the trend in melting points down group 2?

Answer 7

There is a general decrease however, a rise from Mg to Ca.

Question 8

Why is there a general decrease in melting points down group 2?

Question 9

Why is there a rise in melting points between Mg and Ca?

Answer 9

There is a change in the trend after Mg due to a change in the way atoms (ions) pack together (they pack together in a closer arrangement).

Question 10

What would you observe when Mg reacts with water?

Answer 10

No reaction/very slow.

Question 11

What is the equation of Mg reacting with water?

Answer 11

Mg + H20 -> Mg(OH)2 + H2

Question 12

What would you observe when Mg reacts with steam?

Answer 12

Bright white flame, white precipitate forms.

Question 13

What is the equation of Mg reacting with steam?

Answer 13

Mg + H2O -> MgO +H2

Question 14

What would you observe when Ca reacts with water?

Answer 14

Fizzes, cloudy (precipitate formed over time), bubbles, not very soluble in water.

Question 15

What is the equation of Ca reacting with water?

Answer 15

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

Question 16

What would you observe when Sr reacts with water?

Answer 16

Fizzing (more vigorously than Ca), forms a colourless solution.

Question 17

What is the equation of Sr reacting with water?

Answer 17

Sr + 2H2O -> Sr(OH)2 + H2

Question 18

What would you observe when Ba reacts with water?

Answer 18

Fizzes in water and forms a colourless solution.

Question 19

What is the equation of Mg reacting with water?

Answer 19

Ba + 2H2O -> Ba(OH)2 + H2

Question 20

What is the trend in reactivity as you go down group 2?

Answer 20

It increases.

Question 21

Why does the reactivity increase as you go down group 2?

Answer 21

As you go down the group, the atomic radius increases as there are more shells. Therefore, the attraction between the positive nucleus and the outer shell electrons is weaker meaning electrons are lost more easily. Also there is more electron shielding.

Question 22

Is Mg(OH)2 soluble or insoluble?

Answer 22

Insoluble.

Question 23

Is Ca(OH)2 soluble or insoluble?

Answer 23

Slightly soluble.

Question 24

Is Sr(OH)2 soluble or insoluble?

Answer 24

Soluble.

Question 25

Is Ba(OH)2 soluble or insoluble?

Answer 25

Soluble.

Question 26

Are precipitates formed when a substance is soluble or insoluble?

Answer 26

Insoluble/slightly soluble.

Question 27

What is the ionic equation for the formation of Mg(OH)2.

Answer 27

Mg2+(aq) + 2OH-(aq) -> Mg(OH)2(s)

Question 28

What is the ionic equation for the formation of Ca(OH)2?

Answer 28

Ca2+(aq) + 2OH-(aq) -> Ca(OH)2(s)

Question 29

Is MgSO4 soluble or insoluble?

Answer 29

Soluble.

Question 30

Is CaSO4 soluble or insoluble?

Answer 30

Slightly soluble.

Question 31

Is SrSO4 soluble or insoluble?

Answer 31

Insoluble.

Question 32

Is BaSO4 soluble or insoluble?

Answer 32

Insoluble.

Question 33

What is the ionic equation for the formation of CaSO4?

Answer 33

Ca2+(aq) + SO42-(aq) -> CaSO4(s)

Question 34

What is the ionic equation for the formation of SrSO4?

Answer 34

Sr2+(aq) + SO42-(aq) -> SrSO4(s)

Question 35

What is the ionic equation for the formation of BaSO4?

Answer 35

Ba2+(aq) + SO42-(aq) -> BaSO4(s)

Question 36

What is the trend in solubility down the group 2 hydroxides?

Answer 36

Increasing solubility.

Question 37

What is the trend in solubility down the group 2 sulfates?

Answer 37

Decreasing solubility.

Question 38

What is used to test for sulfate ions?

Answer 38

Acidified (hydrochloric acid) barium chloride (aq).

Question 39

Why is barium chloride (aq) used to test for sulfate ions?

Answer 39

Barium chloride produces a white precipitate when reacting with sulfate ions - BaSO4(s). This is because BaSO4 is insoluble.

Question 40

Why is the barium chloride acidified (with HCl) when testing for sulfate ions?

Answer 40

This removes any other ions (such as carbonate ions) that could also give a precipitate with barium chloride (aq).

Question 41

What is the use of magnesium?

Answer 41

It is used to extract Ti from the ore rutile (TiO2) TiCl4 + 2Mg -> Ti + 2MgCl2

Question 42

What is the use of BaSO4?

Answer 42

Used for barium meal x-rays - suspension of BaSO4 given to patients to drink, opaque to x-rays to show intestines on x-rays. It is not harmful due to the total insolubility of BaSO4.

Question 43

What is the use of Mg(OH)2?

Answer 43

It is used in milk of magnesia to relieve acid indigestion. The suspension of Mg(OH)2 in water, used in ant acid, neutralises stomach acid but is insoluble so it isn’t corrosive.

Question 44

What is the use of Ca(OH)2?

Answer 44

It is used in slaked lime which reduces the acidity of fields. It is only slightly soluble in water and so excess Ca(OH)2 is not a problem.

Question 45

What is CaO and CaCO3 used for?

Answer 45

CaO + SO2 -> CaSO3 CaCO3 + SO2 -> CaSO3 + H2O CaSO3 is used to make plaster board and both of these reactions remove SO2 from the atmosphere.