Topic 8

Question 1

What metals are in group 1

Answer 1

Alkali

Question 2

Physical properties of alkali metals

Answer 2

Good conductors if heat and electricity

Shiny when freshly cut

However compared to most other metals
Are soft - cut with a knife
Have relatively low melting points (all solid)

Question 3

Alkali + water ->

Answer 3

Alkaline metal hydroxide + hydrogen

Question 4

Reactivity of alkali metals

Answer 4

Increases down group

Lithium fizzes steadily
Sodium melts into a ball from heat released in the reaction and fizzes rapidly

Question 5

Density of alkali metals

Answer 5

Lithium, sodium and potassium are less dense than water so they float

Question 6

Storage of alkali metals

Answer 6

Lithium sodium and potassium are stored in oil this is to keep and water away

Question 7

Rubidium is placed below potassium in the periodic table. Predict what is seen in the reaction of rubidium with water.

Answer 7

Rubidium will react very vigorously with water, producing sparks and bursting into flames explosively

Question 8

Explain why sodium is more reactive than lithium

Answer 8

Sodium atoms are larger than lithium atoms. So the outer electron in a sodium atom is further from the nucleus than the outer electron in a lithium atom
This means that the force of attraction is weaker
So the outer electron is lost more easily from sodium than lithium

Question 9

What are the elements in group 7 called

Answer 9

Halogens

Question 10

Colour of fluorine

Answer 10

Pale yellow

Question 11

Chlorine colour

Answer 11

Yellow-green

Question 12

Bromine colour

Answer 12

Red-brown

Question 13

Iodine colour

Answer 13

Dark grey

Question 14

Melting and boiling points going down group 7

Answer 14

Melting point increase

Boiling point increase

Question 15

When simple molecular forces melt or boil

Answer 15

Wean intermolecular forces are overcome

The strong covalent bonds joining atoms together in each molecule do not break

Question 16

Going down group 7

Answer 16

The intermolecular forces between molecules become stronger

More heat energy is needed to overcome these forces

Question 17

Metal + halogen

Answer 17

Metal hallide

Question 18

In reactions with metals

Answer 18

Halogen atoms gain electrons and are reduced

Question 19

How many atoms do halogens have in there outer shell

Answer 19

7

Question 20

Going down group 7:

Answer 20

The outer shell gets further from the nucleus

There is more shielding by inner electrons

The force of attraction between the nucleus and outer shell electrons gets weaker

Electrons are gained less easily

The elements become less reactive

Question 21

How can you demonstrate a displacement reaction

Answer 21

By adding a halogen solution to a metal halide solution, then seeing if the mixture darkens for example

Chlorine in ‘chlorine water’ displaced from aqueous sodium bromide solution

Question 22

What are redox reactions

Answer 22

Halogen displacement

Question 23

Where are the noble gases

Answer 23

Group 0

Question 24

The noble gases are chemically

Answer 24

Inert

Question 25

Noble gases have a lack of reactivity because

Answer 25

Their atoms have full outer shells of electrons so they have no tendency to lose gain or share electrons

Question 26

Use of helium

Answer 26

Lifting gas in party balloons and airships

Question 27

Reason for helium’s use

Answer 27

Helium is less dense than air so the balloons and airships rise

It is non-flammable so does not ignite

Question 28

Helium properties needed

Answer 28

Low density

Inertness

Question 29

Argon krypton and xenon uses

Answer 29

Filling gas in filament lamps

Question 30

Property needed in argon krypton and xenon

Answer 30

Inertness

Question 31

Reason for use (argon krypton xenon)

Answer 31

The metal filament becomes hot enough to glow

The inert gases stop it burning away

Question 32

Argon use

Answer 32

Shield gas during welding

Question 33

Property needed for argon

Answer 33

Inertness

Question 34

Reason for argon use

Answer 34

Argon is gender than air so it keeps air away from the metal

It is inert so the metal does not oxidise

Question 35

Colliding particles

Answer 35

For s reaction to happen:
Reactant particles must collide with each other and
The collisions must have enough energy

Question 36

What’s activation energy

Answer 36

The minimum energy needed by a reaction particles for a reaction to happen

A successful collision has the activation energy of more

Question 37

Rate and time o reactions

Answer 37

The greater the rate of reaction the lower the reaction time

A fast reaction happens in a short time such as combustion

A slow reaction happens over a long time such as rusting

Question 38

Concentration and pressure

Answer 38

The rate of reaction increases if the concentration of a dissolved reactant increased or if the pressure of a reacting gas increases

There are more particles in the same volume

The frequency of successful collisions increases

Question 39

Temperature

Answer 39

The rate of reaction increases when the temperature increases because the particles gain energy and
The particles move faster
The frequency of collisions increases and the energy of collisions increases so a greater protoitduin of collisions are successful

Question 40

Surface area : volume ratio

Answer 40

The rate of reaction increases when the sa:v ratio of a solid reactant increases eg when lumps are made into a power

More particles of a reactant are available
The frequency of successful collisions increases