TOPIC 4: INORGANIC CHEMISTRY & THE PERIODIC TABLE

Question 1

Describe the Trend in ionisation energy of Group 2

Answer 1

As you go down group 2, number of shells increase means increased shielding.There is a lower attraction between the outer electron and nucleus so ionisation energy decreases

Question 2

Describe the Trend in reactivity down Group 2

Answer 2

The reactivity increases as you go down the group as outer electrons are more easily lost

Question 3

Equation of GROUP 2 element reacting with water

Answer 3

Metal (solid)+ 2Water (liquid)- Metal Hydroxide (aqueous)+ Hydrogen (gas)

Question 4

Equation of GROUP 2 element reacting with oxygen

Answer 4

Metal (solid)+ Oxygen (gas) -2Metal Oxide (solid)

Question 5

Equation of GROUP 2 element reacting with chlorine

Answer 5

Metal (solid)+ Chlorine (gas)- Metal Chloride( solid)

Question 6

Exceptions on solubility

Answer 6

1. Beryllium oxide- does not react with water and beryllium hydroxide isn’t very soluble.
2. Magnesium oxide-reacts slowly and magnesium hydroxide is not very soluble.
3. Barium sulfate is insoluble

Question 7

Trends in solubility down Group 2 hydroxides + sulfates

Answer 7

1. Singly charged metal hydroxides increase in solubility down the group.
2. Doubly charged metal sulfates decrease in solubility down the group.

Question 8

Equation for metal oxide + water

Answer 8

metal oxide (solid)+ Water (liquid)-Metal hydroxide (aqueous)

Question 9

Equation for metal hydroxide with water

Answer 9

Metal hydroxide (solid)+Water (liquid)- Metal hydroxide (aqueous)

Question 10

Equation for metal oxide with dilute hydrochloric acid

Answer 10

Metal oxide (solid)+2 HCL (aqueous)-Metal chloride (aqueous)+ Water (liquid)

Question 11

Equation for metal hydroxide with dilute hydrochloric acid

Answer 11

Metal hydroxide (aqueous)+ 2HCl (aqueous) - Metal chloride (aqueous)+ 2Water (liquid)

Question 12

Thermal decomposition

Answer 12

When a substance breaks down when heated

Question 13

Which ion polarises which ion?

Answer 13

The cation polarises the anion distorting it

Question 14

Difference in thermal stability between group 1 and group 2 carbonates/nitrates

Answer 14

Group 2 compounds are less stable than group 1 as they have a higher charge density

Question 15

Relationship between charge density of a cation and thermal stability

Answer 15

The greater the charge density the more the anion is polarised (distorted) the less thermally stable the compound

Question 16

Thermal decomposition of Group 1 carbonates

Answer 16

Group 1 carbonates do not thermally decompose under a bunsen flame

an exception is lithium carbonate(solid)- Lithium oxide (solid)+ carbon dioxide (gas)

Question 17

Thermal decomposition of Group 1 nitrates

Answer 17

Group 1 nitrates thermally decompose to form a nitrite and oxygen

General formula: Metal nitrate (solid) - 2Metal nitrite (solid)+ Oxygen (gas)

Question 18

What is the exception for the thermal decomposition of the Group 1 nitrates

Answer 18

Lithium nitrate(solid)- Lithium oxide (solid)+ Nitrogen oxide (gas)+ Oxygen (gas)

Question 19

Thermal decomposition of Group 2 carbonates

Answer 19

Group 2 carbonates thermally decompose to form the oxide and carbon dioxide

General formula: Metal carbonate (solid)- Metal oxide (solid)+ Carbon dioxide (gas)

Question 20

Thermal decomposition of Group 2 nitrates

Answer 20

Group 2 nitrates thermally decompose to form the metal oxide, nitrogen dioxide and oxygen

General formula: 2Metal nitrate (solid)- 2Metal oxide (solid)+ 4Nitrogen dioxide (gas)+ Oxygen (gas)

Question 21

How to test for carbonates

Answer 21

1. See if carbon dioxide is produced

2. Lime water(calcium hydroxide) turns cloudy if carbon dioxide present

Question 22

How to test for nitrates

Answer 22

1. See if oxygen is produced
2. If glowing splint is relit oxygen is present
3. Nitrogen oxide is a brown gas and is toxic so has to be done in a fume cupboard

Question 23

Lithium flame colour

Answer 23

red

Question 24

Sodium flame colour

Answer 24

Orange/yellow

Question 25

Pottasium flame colour

Answer 25

Lilac

Question 26

Rubidium flame colour

Answer 26

red

Question 27

Caesium flame colour

Answer 27

blue

Question 28

Calcium flame colour

Answer 28

Brick red

Question 29

Strontium flame colour

Answer 29

Crimson red

Question 30

Barium flame colour

Answer 30

green

Question 31

How to do a flame test

Answer 31

1. Mix a small amount of the compound with a few drops of hydrochloric acid. 2. Heat a nichrome wire in a bunsen flame to sterilise it. 3. Dip the wire in the compound and hold it in the hot flame and observe colour produced.