Atomic structure, states of matter, periodic table, experimental techniques

Question 1

non metal ion [1]

Answer 1

Gains electrons and becomes negative ion

Question 2

Explain why 2 isotopes of bromine have the same chemical propoerties [2]

Answer 2

1) same number of electrons
2) same electronic configuration

Question 3

Atomic number define

Answer 3

Number of protons in an atom

Question 4

Element define

Answer 4

Substance made up of 1 type of atom

Question 5

Compound define

Answer 5

Substance made up of two or more types of elements

Question 6

Why does an element behaves like a non-metal [2]

Answer 6

1) Gains electrons for stability
2) More electrons than protons in an atom forms negative ion

Question 7

Solvent vs solute [2]

Answer 7

The solute is the substance that is being dissolved, while the solvent is the dissolving medium

Question 8

The diagram shows the arrangement of the particles in a pure metal.
Metals are often made into alloys to make them harder.
Explain why alloys are harder than pure metals.
Draw a diagram to support your answer.
[4]

Answer 8

Pure metal:

(Particles / ions / atoms are the same size in a regular arrangement so) layers can easily slide over each other; [1 mark]
Alloy:

Diagram of alloy structure showing a minimum of three layers with at least one different-sized circle; [1 mark]
(Having different sized particles breaks up the regular arrangement; [1 mark]
So, it is hard(er) for layers to slide over each other; [1 mark]
[Total: 4 marks]

Question 9

Both iron andsteel have typical metallic structures - a latticeofpositiveions anda sea of electrons.
i)
Explain why iron and steel havehigh meltingpoints.
[2]
ii)
Explain why, when a force is applied to a pieceof steel, itdoes not breakbutchanges its shape.

Answer 9

i) Lots of strong electrostatic forces that require a lot of energy to break

ii) The lattice can slide past each other

Question 10

Are alloys chemically combined

Answer 10

false

Question 11

This question is aboutmetals andnon-metals.
Comparetheproperties ofmetals andnon-metals.
[4]

Answer 11

1) Metals conduct heat and electricity
AND
Non-metals do not conduct heat and electricity
2) Metals are malleable
AND
Non-metals are brittle
3) Metals are shiny
AND
Non-metals are dull
4) Metals have high density
AND
Non-metals have low density

Question 12

Give three example of a property of Group I metals that is different from most other metals.
[3]

Answer 12

Low density
Low melting point
Soft

Question 13

Define alloy

Answer 13

A mixture of more than 1 metal and other elements

Question 14

Rf formula

Answer 14

Distance travelled by solute / distance travelled by solvent

Question 15

explain
filtration

Answer 15

Filtration : Used to separate an insoluble solid from a mixture of the solid and a liquid / solution ( e.g. sand from a mixture of sand and water).

Question 16

Crystallisation is used for what

Answer 16

Crystallisation: Used to separate a dissolved solid from a solution, when the solid is more soluble in hot solvent than in cold (e.g. copper sulphate from a solution of copper (II) sulphate in water)

Question 17

simple and fractional distillation is used for what [2]

Answer 17

Simple Distillation

Used to separate a liquid and soluble solid from a solution (e.g. water from a solution of saltwater) or a pure liquid from a mixture of liquids

Fractional distillation

A mixture of liquids that is separated by (different) boiling points; (e.g. ethanol and water from a mixture of the two)

Question 18

Mass number

Answer 18

number of protons/neutrons

Question 19

what define a period in a periodic table

Answer 19

number of shells in element

Question 20

Mixture vs compound [4]

Answer 20

1) Mixture is physically combined
2) Compound is chemically combined
3) Mixture can be separated by physical means
4) Compounds have fixed melting & boiling points

Question 21

Why is alloy preferred than pure metals?

Answer 21

Alloys can be harder and stronger than the pure metals and are more useful

Question 22

elements in the 1st period

Answer 22

Hydrogen & helium

Question 23

Lithium, beryllium, boron, carbon… etc are part of which period?

Answer 23

2

Question 24

Why is neon unreactive?

Answer 24

Neon has a full outershell

Question 25

Alkaline metals’ reactivity and why [4]

Answer 25

1) Reactivity of group 1 increase down the group
2) As you move down the outer shell gets further away from the nucleus and there is more shielding
from inner electrons
3) Force of attraction between positively charged nucleus and the negatively charged electrons gets weaker
4) therefore the more electron shells an alkali metal has, the easier the electron is lost, the more reactive it is

Question 26

Why might halogens become less reactive as you go down the group? [3]

Answer 26

1) halogens wants to gain 1 electron in the outershell for stability
2) Force of attraction is weaker the more shells an atom has
3) The more energy shells down the group, the harder it is to retain the electron, therefore it is less reactive.

Question 27

Simplified steps for chromatography [4]

Answer 27

1) Draw a pencil line to create the mobile phase
2) drop the dyes on the line
3) Place the chromatography paper into the beaker, spots must be above the liquid level
4) record the data for rf values

Question 28

Define chromatogrpahy

Answer 28

Separate mixtures of soluble coloured and colourless substances, using a suitable solvent and a locating agent

Question 29

2 common mistakes in chromatography [2]

Answer 29

1) Using pen
2) Placing paper too deep into the solution so spots are under solvent

Question 30

How to tell if a substance is pure? [2]

Answer 30

1) The boiling/melting point
2) The line should be straight on a graph if plotted

Question 31

Properties of solid, liquid, gas [9]
(Volume, shape, compressibility)

Answer 31

1) Volume: solid is definite, liquid is definite, gas occupy container
2) Compressibility: cannot be compressed solid, cannot compressed liquid, highly compressed gas
3)Shape: Definite shape solid, no shape liquid, no shape gas

Question 32

Structures of solid, liquid, and gas [9]

Answer 32

1) particle separation: Solid are tightly packed, liquid are close, gas are well separated
2) arrangement: Solid is regular, liquid is irregular, gas is irregular
3) motion: Solid vibrate around fixed point, liquid move randomly, gas move randomly

Question 33

Explain the effects of temperature and pressure on the volume of a gas [3]

Answer 33

1) Increase temperature means increase kinetic energy moving faster and more collison
2) Pressure is increased by the collision
3) The volume is smaller because particles are more closely packed

Question 34

Gas pressure

Answer 34

The force exerted by gas particles colliding with surfaces of ojects or other particles

Question 35

Diffusion

Answer 35

Movement of particles from high to low concentration

Question 36

Describe and explain the effect of relative
molecular mass on the rate of diffusion of gases [1]

Answer 36

the larger the molecule and the higher its molecular weight, the slower is its rate of diffusion.

Question 37

Rate of diffusion affected by [4]

Answer 37

1) temperature
2) diffusion distance
3) concentration gradient
4) mass of particles

Question 38

Explaining why the bromine molecules have spread uniformly to occupy the whole container [3]

Answer 38

Diffusion
Random movement of molecule
Bromine is a fluid with room for molecules to move

Question 39

Explaining why the pressure increases when the temperature is increased[2]

Answer 39

The particles have more energy
They collide more frequently

Question 40

Techniques used for

Water from sea-water

Helium from a mixture of helium and methane:

Ethanol from a mixture of ethanol and propanol:

Iron filings from a mixture of iron filings and water:

A mixture of two amino acids, glycine and alanine
[5]

Answer 40

Simple distillation; [1 mark]

Fractional distillation / diffusion; [1 mark]

Fractional distillation; [1 mark]

Filtration / evaporation; [1 mark]

Chromatography; [1 mark]

Question 41

Oxygen from liquid air separation

Answer 41

Fractional distillation; [1 mark]

(Liquid air is a mixture of liquids with different boiling points so fractional distillation is the most appropriate technique)

Question 42

Checking the reliability of the results in chromatogrpahy [3]

Answer 42

You could repeat the experiment;
OR

Use a different solvent;

OR

Measure the Rf values

Question 43

The order of elements in a period is determined by

Answer 43

Atomic number / proton number / number of protons (in one atom); [1 mark]

Question 44

What do we call the line made by the solvent when we
take it out the beaker?

Answer 44

Solvent line

Question 45

Explaining, using kinetic particle theory, why gases diffuse [2]

Answer 45

The particles move in random motion; [1 mark]
The particles collide; [1 mark]
The particles move from a region of high concentration to low concentration; [1 mark