C1: Atomic Structure

Question 1

What is an element?

Answer 1

A substance with same-type atoms

Question 2

What is a compound and what are their properties?

Answer 2

2 or more different elements that are chemically combined in fixed proportion.
They have different chemical properties to the elements they’re made of.
The elements can be separated again using chemical separation techniques.

Question 3

What is a mixture?

Answer 3

Different elements or compounds that are not chemically combined.
They are separated using physical separation techniques.

Question 4

What is a molecule?

Answer 4

Any elements which are chemically combined, even if they’re the same type.

Question 5

What are the physical separation techniques?

Answer 5

Filtration
Crystallisation
Distillation
Chromatography

Question 6

What is filtration?

Answer 6

The process of separating an insoluble solid from a liquid

Question 7

Describe the process of filtration

Answer 7

Pour mixture into filter paper, which is over a filter funnel. The liquid passes through the funnel and into a beaker underneath the funnel, whereas the solid material sticks to the filter paper.

Question 7

What is crystallisation?

Answer 7

The process of separating a soluble solid from a liquid

Question 8

Describe the process of crystallisation

Answer 8

Place mixture in an evaporating basin and hold over a Bunsen burner, until most of the water evaporates. It will leave a little water and some salt. Leave on a towel to dry and form crystals

Question 9

What is simple distillation?

Answer 9

Used to separate a liquid from a solid by taking advantage of differing boiling points. Also used if you want to keep the liquid

Question 10

What is fractional distillation?

Answer 10

Used to separate a liquid from a liquid by taking advantage of differing boiling points

Question 11

Describe the setup of simple distillation

Answer 11

Place solution into a round bottom flask, which is connected to a continuous glass tube, which is surrounded by a jacked (condenser). Cold water/ ice is into the condenser, which cools down the liquid. The tube goes into another beaker. A thermometer is also included.

Question 12

Describe the process of simple distillation

Answer 12

Heat the solution. The liquid will start to evaporate, rise up the glass tube and the thermometer will show a temp rise. The vapour passes through the condenser, and turns back into a liquid and is collected into a beaker.

Question 13

What is the plum-pudding model?

Answer 13

A ball of positive charge with negative electrons embedded in it. (Early model of the atom)

Question 14

What is the alpha-scattering experiment?

Answer 14

Scientists took a piece of gold foil (can be hammered into a few atoms thick). They fired tiny alpha particles (Positively charged). They noticed that some of them just passed through without changing direction. Sometimes it was deflected, and other times it completely bounced off.

Question 15

What did the alpha-scattering experiment conclude?

Answer 15

Atoms are mainly empty space.
The centre of the atom had a positive charge.
The mass of the atom is concentrated in the centre.

Question 16

What is the nuclear model?

Answer 16

Where most of the atom is mostly empty space, with a positive nucleus and a cloud of electrons.

Question 17

What did Bohr propose?

Answer 17

The electrons orbit the nucleus at specific distances (as a cloud of electrons would cause the atom to collapse) and it agreed with the results of experiments of other scientists.

Question 18

What did Chadwick propose?

Answer 18

Nucleus also contains neutrons

Question 19

What is the radius of the atom?

Answer 19

0.1nm (1*10^-10m)
Approximation, some atoms larger than others

Question 20

What is the radius of the nucleus?

Answer 20

1*10^14m

Question 21

What are the masses of subatomic particles?

Answer 21

Proton - +1, 1
Neutron - 0 1
Electron - -1 1/1000 (very small?)

Question 22

What is an isotope?

Answer 22

Atoms of an element with different numbers of neutrons.

Question 23

What is an ion?

Answer 23

Atoms with have an overall charge - they have gained or lost electrons.

Question 24

What is the atomic mass of an element?

Answer 24

The total number of protons and neutrons of an atom

Question 25

What is the atomic number of an element?

Answer 25

Number of protons in an atom of the element

Question 26

What is the relative atomic mass of an element?

Answer 26

The average of the mass numbers of the different isotopes, weighted for the abundance of each isotope.