C1 atomic structure

Question 1

what is an atom

Answer 1

All substances are made of atoms. An atom is the smallest part of an element that can exist.

Question 2

what is an element

Answer 2

an element is a substance which only contains one type of atom

Question 3

what is a compound

Answer 3

a compound is a substance which contains atoms from 2 or more elements which are chemically combined in fixed proportions

Question 4

what is the charge of protons

Answer 4

+1 they are positively charged

Question 5

what is the charge of electrons

Answer 5

-1 they are negatively charged

Question 6

what is the charge of neutrons

Answer 6

0 they are neutral

Question 7

what is a mixture

Answer 7

two or more elements or compounds not
chemically combined together

Question 8

what is filtration

Answer 8

Filtration is used to separate an insoluble solid from a liquid. It is useful for separating sand from a mixture of sand and water, or excess reactant from a reaction mixture.

Question 9

what is crystallization

Answer 9

Crystallisation is used to produce solid crystals from a solution. When the solution is warmed, some of solvent evaporates leaving crystals behind. For example, crystallisation is used to obtain copper sulfate crystals from copper sulfate solution.

Question 10

how do you separate a mixture using crystallization

Answer 10

put the solution in an evaporating basin
warm the solution by placing the evaporating basin over a boiling water bath
stop heating when crystals begin to form around the edge of the basin

Question 11

what is simple distillation

Answer 11

Simple distillation is used to separate a solvent from a solution

Question 12

how does simple distillation work

Answer 12

Simple distillation works because the dissolved solute has a much higher boiling point than the solvent.
When the solution is heated, solvent vapour leaves the solution. It moves away and is cooled and condensed.
The remaining solution becomes more concentrated as the amount of solvent in it decreases.

Question 13

what is fractional distillation

Answer 13

Fractional distillation is used to separate different liquids from a mixture of liquids.

Question 14

what is chromatography

Answer 14

Paper chromatography is used to separate mixtures of soluble substances. These are often coloured substances such as food colourings, inks, dyes or plant pigments.

Question 15

what were atoms originally thought to be

Answer 15

Before the discovery of the electron, atoms were thought to be tiny spheres that could not be divided.

Question 16

what did the discovery of an electron lead to and who created it

Answer 16

thomsons discovery of the electron led to the plum pudding model of the atom. The plum pudding model suggested that the atom is a ball of positive charge with negative electrons embedded in it

Question 17

what were the results from the alpha particle scattering experiment

Answer 17

The results from the alpha particle scattering experiment led to the conclusion that the mass of an atom was concentrated at the centre (nucleus) and that the nucleus was charged. This nuclear model
replaced the plum pudding mode

Question 18

how do you find the number of protons

Answer 18

the atomic number

Question 19

how do you find the number of neutrons

Answer 19

mass number - atomic number

Question 20

what is the radius of an atom

Answer 20

1 x 10-10 m

Question 21

what is the radius of the nucleus

Answer 21

1 x 10-14 m

Question 22

what is the relative mass of a proton

Answer 22

1

Question 23

what is the relative mass of a neutron

Answer 23

1

Question 24

what is the relative mass of an electron

Answer 24

very small

Question 25

what is an isotope

Answer 25

Atoms of the same element can have different numbers of
neutrons but the same number of protons