Chemistry Year 9 Autumn Term Assessment

Question 1

Define Element

Answer 1

An element is a substance made up of only 1 type of Atom.

Question 2

Define Compound

Answer 2

A compound is more than one type of atom chemically joined together.

Question 3

What is the mass and charge of a PROTON ?

Answer 3

Mass = 1
Charge = +1

Question 4

What is the mass and charge of a NEUTRON ?

Answer 4

Mass = 1
Charge = 0

Question 5

What is the mass and charge of a ELECTRON ?

Answer 5

Mass = almost 0
Charge = -1

Question 6

What does the nuclear model of the atom have?

Answer 6

A shell with 2 electrons

A nucleus with protons an neutrons

Question 7

Explain Paper Chromatography

Answer 7

Chromatography can be used to separate mixtures of coloured compounds.Mixtures that are suitable for separation by chromatography include inks, dyes and colouring agents in food.

Question 8

Explain the method

Answer 8

1. Draw a 2 cm baseline with a PENCIL on a piece of chromatography paper..
2. Place 3 pure colours on the baseline and a unknown colour.
3. Then the place the chromatography paper in a solvent but don’t let it touch the colours on the baseline as the colours will dissolve in the water.
4. As the solvent soaks up the paper it carries the mixture with it but the components will move at different rates.
5. finally compare the unknown to the know and draw a solvent front to show where the colours stop.

Question 9

Group 0 - Alkali metals

List the properties

Answer 9

• very reactive
• stored in oil to stop it reacting with water and air
• these metals are soft - can be cut with a knife
• dull and only shiny once cut
• have low density so therefore they float in water
• reactivity increase as you go down the group- this means that the outer shell electron gets further away from the nucleus and is shielded by more electrons.This means the further away an electron is from the nucleus the easier it can be lost.

Question 10

Group 7 - Halogens

List the properties

Answer 10

• Melting and boiling point increase going down the group as the molecules become bigger
• have similar chemical properties
• the reactivity decrease as the atoms get large going down this means that the outer shell gets further away from the nucleus. The shell is further so its hard to attract another electron.