Inorganic Chemistry and the Periodic Table

Question 1

Explain the trend in Ionisation Energies down Group 2

Answer 1

• Ionisation Energies Decreases
• Down the group number of shells increase
• The positive charge nucleus is increased as you go down the Group but is counter affected by increase shielding
• Overall This will lead to a greater distance from a nucleus weakening electrostatic attraction

Question 2

Explain the trend in Reactivity down Group 2

Answer 2

Reactivity increases
Ionisation Energy decreases as you go down the group
Lower activation energies
Outer two electrons can form +2 ions more easily/quicker in reactions

Question 3

What is formed if a Group 2 metal reacts with oxygen

Answer 3

Solid white Metal oxide

Question 4

What is formed if a Group 2 metal reacts with water

Answer 4

Metal hydroxide
Hydrogen

Question 5

What is formed if a Group 2 metal reacts with chlorine

Answer 5

White Solid Chloride

Question 6

What is the flame colour for lithium

Answer 6

Red

Question 7

What is the flame colour for sodium

Answer 7

Yellow

Question 8

What is the flame colour for potassium

Answer 8

Lilac

Question 9

What is the flame colour for beryllium

Answer 9

No flame colour

Question 10

What is the flame colour for calcium

Answer 10

Brick Red

Question 11

What is the flame colour for Strontium

Answer 11

Red

Question 12

What is the flame colour for Barium

Answer 12

Apple Green

Question 13

What is formed if a Group 2 metal oxide reacts with water

Answer 13

Metal hydroxides which dissolve making strongly alkaline solutions
Except Beryllium oxide

Question 14

What is formed if a Group 2 metal hydroxide reacts with oxygen

Answer 14

Metal hydroxides

Question 15

What is formed if a Group 2 metal oxide reacts with a dilute acid

Answer 15

Salt
Water

Question 16

What is formed if a Group 2 metal hydroxide reacts with a dilute acid

Answer 16

Salt
Water

Question 17

Describe the trend in solubility of hydroxides

Answer 17

Solubility increases as you go down the group

Question 18

Describe the trend in solubility of sulphates

Answer 18

Solubility decreases as you go down the group

Question 19

Define ‘Thermal Decomposition’

Answer 19

Thermal Decomposition is when a substance breaks down when it is heated

Question 20

Define ‘Thermal Stability’

Answer 20

An indication of how easily a compound thermally decomposes.

Question 21

Explain the thermal stability of Group 1 Nitrates and Carbonates com[pared with Group 2

Answer 21

Group 1 Nitrates and Carbonates more more thermally stable than Group 2
- Smaller ionic charge
- Less distortion
- Weaker polarising power

Question 22

Explain the trend in thermal stability of Group 2 Nitrates and Carbonates

Answer 22

Thermal Stability increases down Group 2
- Size of Charge remains the same but Ionic radius increases so charge density decreases
- leading to lower polarising power
- distorts the anions(nitrate/carbonate ion) less resulting in in strong bond
- requires more energy to break

Question 23

What is formed when a Group 2 carbonate is thermally decomposed

Answer 23

• Metal Oxide
• Carbon Dioxide

Question 24

What is formed when a Group 2 nitrate is thermally decomposed

Answer 24

• Metal Oxide(white solid)
• Nitrogen Dioxide(brown gas)
• Oxygen(colourless gas)

Question 25

What is formed when a Group 1 carbonate is thermally decomposed

Answer 25

Group 1 compounds are thermally stable Except Lithium Carbonate which forms a metal oxide and carbonate

Question 26

What is formed when a Group 1 nitrate is thermally decomposed

Answer 26

Metal Nitrite Oxygen except

Question 27

Describe the trends of melting and boiling points of the halogens

Answer 27

Boiling and Melting points increase down group 7 More electron shells resulting in more electrons Increase strength of London Dispersion Forces

Question 28

Describe the trend in electronegativity of the halogens

Answer 28

Decreases down group 7 More electron shells (increase shielding) Greater distance from nucleus between bonding pair of electron Reducing electrostatic attraction

Question 29

State the physical states of halogens at R.T

Answer 29

Cl - gas Br- liquid I - solid

Question 30

Describe the trend in reactivity of the halogens

Answer 30

Decreases down group 7 More electron shells greater shielding, greater distance from the nucleus Weaker electrostatic attraction for an additional electron to bond with

Question 31

What happens when you react a halogen with a halide ion in an aqueous solution

Answer 31

The more reactive halogen will oxide the halide For example Chorine oxidises bromide and iodide ions making it the greatest oxidising agent out of the three Bromine oxidises iodide ions but not chlorine Iodine cant do any except theoretically astatide This all means that oxidising ability falls as you go down the Group.

Question 32

What are the colours are the halogens in an aqueous solution?

Answer 32

Cl2 - Palest Green Br2 - Yellow I2 - Brown

Question 33

What are the colours are the halogens in an organic solution?

Answer 33

Cl2 - Palest Green Br2 - Red I2 - Violet

Question 34

State the reaction between chlorine and water and why is it useful

Answer 34

Disproportionate Cl2 + H20 -->(reversible) HCl + HOCl(chloric acid) Use in swimming pools/water treatment

Question 35

State the reaction between chlorine and cold, dilute alkali and why is it useful

Answer 35

Cl2 + 2NaOH --> NaCl + NaClO+ H20 Sodium chlorate is used for killing bacteria in bleach

Question 36

State the reaction between chlorine and hot concentrated alkali and why is it useful

Answer 36

Cl2 + 6NaOH --> 5NaCl + NaClO3 + 3H20

Question 37

Describe the trend of reducing power of the halides by the reaction between sulphuric acid and a halide

Answer 37

Reducing Power Increases as you move down the group Fluoride ions aren't a strong enough reducing agent to reduce H2SO4 Chloride ions reduce H2SO4 to HCL(steamy fumes) Bromide ions reduce to SO2(acidic chocking gas) Iodide ions reduce to S(yellow solid) or H2S(rotten eggs)

Question 37

State the colour of the precipitates of the halide with silver nitrate solution

Answer 37

Chloride - White Bromide - Cream Iodide - Yellow

Question 37

State the colour of the precipitates of the halide with silver nitrate solution followed by aqueous ammonia solution

Answer 37

AgCl - precipitate dissolves to give a colourless solution AgBr - precipitate is almost unchanged using dilute ammonia solution, but dissolves in concentrated ammonia solution to give a colourless solution AgI - precipitate is insoluble in ammonia solution of any concentration

Question 38

Why is there no observation between silver nitrate solution and fluoride ions?

Answer 38

Silver Fluoride Dissolves in water

Question 39

State the reaction between Hydrogen Halide and water

Answer 39

H2O + HCl ---> H3O+ + Cl-

Question 40

State the reaction between Hydrogen Halide and ammonia

Answer 40

NH3(g) + HCl(g) → NH4Cl(s)

Question 41

How do you test for carbonate ions?

Answer 41

Add an aqueous acid (HCL) to form CO2 Bubble it through limewater which should change from clear to cloudy

Question 42

How do you test for sulphate ions

Answer 42

First add HCl to remove any impurities Add barium chloride to form barium sulphate Barium sulphate is insoluble and will form a precipitate

Question 43

How do you test for ammonium ions?

Answer 43

Add sodium hydroxide and the ammonium compound together then heat it to produce ammonia gas Use damp red litmus paper and it should change from red to blue

Question 44

State the half equation for the test of carbonate ions

Answer 44

2H+ + C03 --> C02 + H20

Question 45

State the half equation for the test of sulphate

Answer 45

Ba2+ + S04(2-) ---> BaS04

Question 46

State the ionic/half equation for ammonium ions

Answer 46

OH- + NH4+ --> NH3 + H20