3.2.2 - group 2 the alkaline earth metals

Question 1

Trend in atomic radius down group 2

Answer 1

Atomic radius increases as you go down the group

Question 2

Why does atomic radius get bigger Down group 2

Answer 2

Increased number of e-
Increased number of shells

Question 3

Electronegativity down group 2 trend ?

Answer 3

Decreases down group 2

Question 4

Why does electronegativity decrease down group 2

Answer 4

Increased number of shells
Increased dist from nucleus
Nucleus cannot attract electrons in a covalent bond so easily

Question 5

Trend in mp down group 2

Answer 5

Melting points decrease down group 2

Question 6

Why does melting point decrease down group 2

Answer 6

As you go down the group
Metal becomes bigger so e- further away from positive ions and thus have less electrostatic attraction so less energy needed to overcome bonds

Question 7

Trend in ionisation energies down group two

Answer 7

First ionisation energy decreases down the group

Question 8

Ionisation energy decreases down group 2 because

Answer 8

Each element down group 2 has an extra electron shell compared to the one above
The extra inner shells shield the outer e- from attraction of the nucleus
Extra shell outer e- further from nucleus, weaker attraction so e- can be removed more easier

Question 9

Reactivity down group 2

Answer 9

As you go down the group reactivity increases

Question 10

Group 2 metals more reactive down the groupwhy

Answer 10

As you go down the group first ionisation energy decreases
This is due to increasing atomic radius and shielding effect
When group 2 metals react they loose e-., the easier to loose e- (lower the first nd second ionisation energy) the more reactive the element so reactivity increases down the group

Question 11

Group 2 metals + water gives

Answer 11

Metal hydroxide + hydrogen

Question 12

When group 2 metals react with water the water acts as

Answer 12

Oxidising agent

Question 13

Trends in solubility of hydroxides down group 2

Answer 13

Hydroxides increase in solubility down the group

Question 14

Trend in solubility of sulphites down group 2

Answer 14

Sulphates decrease in solubility down the group

Question 15

Although sulfates decrease in solubility did a group they are still somewhat soluble what is the anomaly

Answer 15

Barium sulfate (BaSO4)

Question 16

Baso4 forms a _____ precipitate

Answer 16

White precipitate

Question 17

Use of barium sulfate not in med

Answer 17

Used to test for sulphate ions

Question 18

Test for sulphate ions

Answer 18

Add acidified barium chloride (Bacl2)
A white ppt of barium sulfate will form (+ve test result)

Question 19

Why is acidified barium chloride used in test for sulphate ions

Answer 19

To remove ions that will also produce white ppt giving false positive

Question 20

Use of barium sulfate

Answer 20

Barium meals to absorb x rays. It’s insoluble and not absorbed by the body so it’s harmless.

Question 21

Due to greater reactivity of barium its …

Answer 21

Stored in oil to keep out of contact with air

Question 22

Grouo 2 metals and oxygen form

Answer 22

Solid metal oxides that are white in colour

Question 23

Mg and cold water form ..
Give equation

Answer 23

Magnesium hydroxide and hydrogen gas

Mg (s) + 2 H2O (l) → Mg (OH)2 (aq) + H2 (g)

Question 24

Mg reacts w steam produces …
Observation…
Equation…

Answer 24

Hot magnesium reacts with steam vigorously producing a ( bright light, white powder these are the observations ) and
forming magnesium oxide and hydrogen gas.
Mg (s) + H2O (g) → MgO (s) + H2 (g)

Question 25

Reactivity of group 2 metals w water down the group

Answer 25

Down the group, the metals react more rapidly with water

Question 26

Trend in ph of hydroxide solutions down the group and why

Answer 26

The pH of hydroxide solutions increases down the group. This is because of the solubility of hydroxides in water increases down the group

Question 27

Solubility of (MgOH)2

Answer 27

Almost insoluble

Question 28

Use of mgoh2

Answer 28

Aid indigestion By neutralising excess stomach acids

Question 29

Use of (CaOH)2

Answer 29

agriculture to neutrialise acid soils

Question 30

Is caoh 2 soluble or insoluble

Answer 30

Soluble More than mgoh2, more hydroxide ions prod so higher ph more alkaline

Question 31

Magnesium is used in extracting ______ from its ore

Answer 31

Titainium

Question 32

1st step of extracting titanium from its ore

Answer 32

Titanium oxide is converted to titanium(IV) chloride by heating it with chlorine and coke (a form of carbon) at 1000 ⁰C ● TiO2 + 2Cl2 + 2C → TiCl4 + 2CO

Question 33

2nd step of extracting tit w mg

Answer 33

Titanium iv chloride is reduced by mg Purified by frac dist TiCl4(l) + 2Mg(s) → Ti(s) + 2MgCl2(s)

Question 34

What group 2 compounds are used to remove sulfur dioxide from flue gases

Answer 34

Calcium oxide Calcium carbonate Alkalis

Question 35

Name of process removing so2 w cao or caco3

Answer 35

Wet scrubbing

Question 36

Wet scrubbing equation for cao

Answer 36

CaO (s) +2H2o (l) + so2 (G) —> CaSo3 (s) + 2H2O (l)

Question 37

Wet scrubbing equation for caco3

Answer 37

CaCO3(s) + 2H2O (l) + SO2 (g) —> CaSO3 (s) + 2H2O (l) +CO2(g)

Question 38

Group 2 elements loose ____ electrons when they react

Answer 38

2

Question 39

Half equation when mg is dissolved in naoh to test solubility

Answer 39

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

Question 40

Mg(OH)2 described as

Answer 40

Sparingly soluble

Question 41

Observation when Ba(OH)2 dissolves

Answer 41

No visible chjage Completely soluble

Question 42

Calcium sulfate equation when dissolved in water

Answer 42

Ca2+ (aq) + SO4 ^2- (aq) —> CaSo4 (s)