Reactivity Trends

Question 1

What are group 2 metals called?

Answer 1

Alkaline Earth Metals

Question 2

What are group 2 metals found as on Earth?

Answer 2

Stable compounds such as calcium carbonate

Question 3

How does the electron configuration of Group 2 metals differ from that of a noble gas?

Answer 3

Two more electrons than the nearest noble gas

Question 4

What is the most common type of reaction of group 2 elements?

Answer 4

Redox

Question 5

What happens to a group 2 metal during a redox reaction?

Answer 5

Oxidised
Loses 2 electrons
Becomes a 2+ ion

Question 6

Is group 2 an oxidising agent or reducing agent? Why?

Answer 6

Reducing agent- reduces another species by being oxidised

Question 7

What is the reaction of a group 2 metal and oxygen?

Answer 7

Group 2 metal + oxygen = Metal Oxide

Question 8

What happens when magnesium burns?

Answer 8

Magnesium burns with a bright light

Question 9

What happens when a group 2 metal reacts with water?

Answer 9

Metal + Water = Metal hydroxide + Hydrogen

Question 10

What happens to reactivity of group 2 metals with water down the group?

Answer 10

Reactivity increases down the group

Question 11

What happens when a group 2 metal reacts with acid?

Answer 11

Metal + Acid = Salt + Hydrogen

Question 12

What happens to reactivity in group 2 metals? Why?

Answer 12

Increases
Requires 2 ionisation energies.
Ionisation energy decreases because of greater shielding and atomic radii.

Question 13

What is the reaction of group 2 oxides with water?

Answer 13

Group 2 oxide + water= metal hydroxide

Question 14

Explain trend in solubility of hydroxides

Answer 14

Increases down the group

Resulting solutions contain more OH- ions

Question 15

Explain trend in alkalinity of hydroxides

Answer 15

Solubility increases
More OH- ions
Increase in pH
Increase in alkalinity

Question 16

What is the pH of magnesium hydroxide?

Answer 16

10

Question 17

What is the pH of barium hydroxide?

Answer 17

13

Question 18

How are group 2 compounds used in agriculture?

Answer 18

Ca(OH)2 are added to fields as lime to increase pH of acidic sols

Question 19

What is the equation of group 2 compounds in agriculture?

Answer 19

Ca(OH)2 (s) + 2H+(aq) = Ca 2+(aq) + 2H20(l)

Question 20

Which 2 group 2 compounds are used in medicine?

Answer 20

CaCO3

Mg(OH)2

Question 21

Give the 2 equations of group 2 compound s in medicine

Answer 21

Mg(OH)2 +2HCl = MgCl2 + 2H20

CaCO3+ 2HCl = CaCl2 +H20 + CO2

Question 22

Where are halogens found?

Answer 22

Sea Water

Potassium and Sodium deposits

Question 23

What is the appearance and state of fluorine at room temperature and pressure?

Answer 23

Pale yellow gas

Question 24

What is the appearance and state of chlorine at room temperature and pressure?

Answer 24

Pale green gas

Question 25

What is the appearance and state of bromine at room temperature and pressure?

Answer 25

Red brown liquid

Question 26

What is the appearance and state of iodine at room temperature and pressure?

Answer 26

Shiny grey-black solid

Question 27

What is the appearance and state of astatine at room temperature and pressure?

Answer 27

Never been seen

Question 28

Explain the trend in boiling points of halogens

Answer 28

More electrons Stronger London forces More energy required to break intermolecular forces Boiling point increases

Question 29

How does the electron configuration of halogens link to that of a noble gas?

Answer 29

One less electron than the nearest noble gas

Question 30

Is a halogen a reducing or oxidising agent?

Answer 30

Oxidising agent, induces oxidation in another species by being reduced

Question 31

What do displacement reactions show?

Answer 31

Reactivity of halogens decreases down the group

Question 32

What colour are chlorine, iodine and bromine in water?

Answer 32

Chlorine- pale green Bromine- orange Iodine- brown

Question 33

What colour are chlorine, iodine and bromine in cyclohexane?

Answer 33

Chlorine- pale green Bromine- orange Iodine- violet

Question 34

Explain the trend in reactivity of halogens

Answer 34

Atomic Radii increases Greater Shielding Less nuclear attraction to capture electron from another species Reactivity decreases

Question 35

What is a disproportionation reaction?

Answer 35

A redox reaction in which the same element is both oxidised and reduced

Question 36

What are 2 examples of disproportionation reactions?

Answer 36

Chlorine with water | Chlorine with cold, dilute sodium hydroxide

Question 37

Write reaction of chlorine with water

Answer 37

Cl2 (aq) +H20 (l) = HClO (aq) + HCl

Question 38

Write reaction of chlorine with cold dilute sodium hydroxide

Answer 38

Cl2 (aq) +2NaOH (aq) = NaClO +NaCl + H20

Question 39

What are the negatives to using chlorine?

Answer 39

Toxic gas Respiratory irritant Can be chlorinated hydrocarbons- which are cancer causing

Question 40

Describe process of carbonate test

Answer 40

Add dilute nitric acid to test tube | See bubbles = carbonate

Question 41

How do you test for CO2?

Answer 41

Add saturated aqueous solution of calcium hydroxide

Question 42

Describe sulfate test

Answer 42

Add Ba2+ ions in the form of barium chloride or nitrate | Barium Sulfate forms which is an insoluble white precipitate if sulfate is present

Question 43

Describe halide test

Answer 43

Add aqueous silver nitrate | Different colour precipitates form

Question 44

What is the equation for the halide test?

Answer 44

Ag +(aq) + X-(aq) = AgX(s)

Question 45

What colours are the halide precipitates?

Answer 45

Chloride- white precipitate Bromide- cream precipitate Iodide- yellow precipitate

Question 46

How does solubility of the halides vary with aqueous ammonia?

Answer 46

Chloride- soluble in dilute NH3 Bromide- soluble in conc. NH3 Iodide- insoluble in conc. NH3

Question 47

What is the correct order of test for anions?

Answer 47

Carbonates Sulfates Halides

Question 48

Why do carbonates have to be tested for before sulfates?

Answer 48

BaCO3 also forms a solid white precipitate

Question 49

How do you test a mixture of chemicals?

Answer 49

Carry out tests in same sequence and on the same solution

Question 50

How do you test for the ammonium ion?

Answer 50

Add aqueous sodium hydroxide Ammonia gas produced Warm Test gas with indicator paper