Inorganic Chemistry

Question 1

How and why does the ionisation energy change down a group?

Answer 1

It decreases since despite there being more protons, the outer s electrons experience more electron shielding and are further from the nucleus.

Remember to refer to specific subshell.

Question 2

What is the oxidation state of a group 2 element?

Answer 2

+2

Question 3

How and why does the reactivity change down group 2?

Answer 3

It increases since the sum of the first two ionisation energies decreases.

Question 4

Reaction of Group 2 Metal with Oxygen

Answer 4

Burn in air to form a metal oxide (eg. CaO).

Question 5

Reaction of Group 2 Metal with Water

Answer 5

Most react quickly to form a salt and H₂.

Mg reacts slowly in cold water. If heated with steam, it burns to form MgO.

Question 6

Reaction of Metal Oxide and Water

Answer 6

Forms a metal hydroxide.

Question 7

Reaction of Metal Oxides and Acid

Answer 7

Forms a salt and water.

Question 8

Reaction of Metal Hydroxides and Acid

Answer 8

Forms a salt and water.

Question 9

Reaction of Limewater with Carbon Dioxide

Answer 9

Ca(OH)₂(aq) + CO₂(g) -> CaCO₃(s) + H₂O(l)

Question 10

How does the solubility of Group 2 Hydroxides change down the group?

Answer 10

It increases.

Question 11

How does the solubility of Group 2 Sulfates change down the group?

Answer 11

It decreases.

Question 12

How does thermal stability change down a group?

Answer 12

It increases.

Question 13

What are the products of the decomposition of metal nitrates?

Answer 13

Group 2 and Lithium: A metal oxide, nitrogen dioxide (brown fumes) and oxygen.

Group 1: A metal nitrite and oxygen.

Question 14

What are the products of the decomposition of metal carbonates?

Answer 14

Group 2 and Lithium: A metal oxide and carbon dioxide

Question 15

Why do cations give colours in a flame test?

Answer 15

The heat energy allows an electron to be promoted to an excited state. This is not stable so the electron drops back to the ground state. The energy released is given off as coloured light with different colours corresponding to different gaps between energy levels.

Question 16

Colour and State of Fluorine?

Answer 16

Pale yellow gas

Question 17

Colour and State of Chlorine?

Answer 17

Green gas

Question 18

Colour and State of Bromine?

Answer 18

Brown liquid

Question 19

Colour and State of Iodine?

Answer 19

Grey-black solid

Question 20

Colour of Chlorine Water?

Answer 20

Pale green

Question 21

Colour of Bromine Water?

Answer 21

Orange

Question 22

Colour of Iodine Solution?

Answer 22

Brown

Question 23

How does the First Electron Affinity change down Group 7?

Answer 23

It decreases down the group though Fluorine’s is lower than Chlorine’s

Question 24

What is the First Electron Affinity?

Answer 24

The energy released when an electron is brought from outside an atom into its outer shell

Question 25

How and why does the reactivity of the halogens change down the group?

Answer 25

It decreases since their electronegativity decreases since the atoms become larger

Question 26

Describe the type of bonding in AlCl₃ and in Al₂Cl₆

Answer 26

In AlCl₃, it is covalent bonds. In Al₂Cl₆, there are two dative covalent bonds between a chlorine atom and an aluminium atom

Question 27

What do the displacement reactions with halogens show?

Answer 27

How powerful an oxidising agent each one is

Question 28

What colour is potassium iodide solution?

Answer 28

Red-brown

Question 29

Reaction of Chlorine with Water

Answer 29

Cl₂(aq) + H₂O(l) ⇌ H⁺(aq) + Cl^-(aq) + HOCl(aq)

Question 30

Which halogen does not react with water?

Answer 30

Iodine

Question 31

How does adding Chlorine to water treat it?

Answer 31

The hydrochloric acid kills off any bacteria in the water