atomic structure

Question 1

What is an atom? ★

Answer 1

The smallest part of an element that can exist.

Question 2

What is an element? ★

Answer 2

A substance made up of only one type of atom.

Question 3

What is a compound? ★

[examples included]

Answer 3

Two or more different elements chemically bonded together in a fixed proportion.

e.g., water, soap, baking soda, sugar etc.

Question 4

What is a mixture? ★

[examples included]

Answer 4

Two or more elements/compounds not chemically combined together.

e.g., sea water, air, ink, crude oil etc.

Question 5

What is shown in a chemical equation? ★

Answer 5

● The reactants (what you start with).
● The products (the new substance).

Question 6

What does it mean to have a balanced symbol equation? ★

Answer 6

There’s the same number of each atom on both sides of the equation.

Question 7

What’s the law of conservation of mass? ★

Answer 7

Total mass of the products formed in a reaction is equal to that of the reactants.

Question 8

What are the state symbols? ★

Answer 8

● s = Solid.
● ʟ = Liquid.
● g = Gas.
● aq = Aqueous solution: substances dissolved in water.

Question 9

What are examples of processes that can separate mixtures? (5) ★

Answer 9

● Filtration
● Crystallisation
● Simple distillation
● Fractional distillation
● Chromatography

Question 10

What is filtration? ★

[include the process]

Answer 10

The physical process which separates insoluble solids from a solution/liquid.
● Insoluble particle remain on filter paper, in filter funnel, as a residue.

Question 11

What is crystallisation? ★

[include the process]

Answer 11

The physical process which separates soluble solids from a solution using evaporation.
● Gently heat the solution to remove water - this leaves the crystals behind.

Question 12

What is simple distillation? ★

[include the process]

Answer 12

The physical process which separates soluble solids from a solution, if you want to keep the liquid.
● Solution boiled to evaporate solvent
● Vapour is cooled so it condenses
● Liquid is collected

Question 13

What’s fractional distillation? ★

Answer 13

The physical process which separates miscible liquids that have different boiling points.

Question 14

What is chromatography? ★

[include process + reason]

Answer 14

The physical process which separates mixtures of substances by dissolving them in a solvent.
● The mixtures of substances move up a piece of chromatographic paper.
● They separate as they have different solubilities in the solvent used.

Question 15

What is a miscible? ★

[examples included]

Answer 15

Liquids that dissolve in each other, mixing completely.

e.g., ethanol + water, lemonade, wine etc.

Question 16

What did the plum pudding model suggest? ★

[include person]

Answer 16

The atom is a ball of positive charge with negative electrons embedded randomly in it.

– JJ Thompson

Question 17

What did the alpha particle scattering experiment conclude? ★

[include person]

Answer 17

● Mass of an atom was concentrated at the centre (nucleus)
● Nucleus was charged - contained dense positively charged protons.
● There were empty spaces.
● Electrons orbited the nucleus.

– Ernest Rutherford

Question 18

What is the last particle to be discovered?

[include reason]

Answer 18

Neutrons as they have no charge.

Question 19

What are the three subatomic particles? ★

Answer 19

Protons, neutrons, electrons.

Question 20

What is the relative charge of the subatomic particles? ★

Answer 20

● Protons = 1+.
● Neutrons = 0.
● Electrons = 1-.

Question 21

Which subatomic particles are (mostly) equal in numbers? ★

Answer 21

Protons and electrons.

Question 22

What is the charge of atoms? ★

[include reason]

Answer 22

It has no overall electrical charge because the number of protons = number of electrons, cancelling the charge.

Question 23

What is the atomic number? ★

Answer 23

Number of protons in an atom of an element.

Question 24

What is different between elements? ★

Answer 24

Their number of protons.

Question 25

What is the size of an atom? ★

[include radius]

Answer 25

Very small.

approximate radius = 0.1nm (1x10^-10m).

Question 26

What is the radius of a nucleus? ★

Answer 26

Radius of nucleus is less than 1/10,000 of the atom.

approximate radius = 1x10^-14m.

Question 27

Where is most of the mass of an atom located?

Answer 27

Nucleus.

Question 28

What is the relative mass of the subatomic particles? ★

Answer 28

● Proton = 1
● Neutron = 1
● Electron = nearly 0 (1/2000)

Question 29

What is an isotope? ★

Answer 29

Atom of the same element with different numbers of neutrons.

Question 30

How do properties of isotopes differ?

Answer 30

● Chemical properties are identical as they have the same number of electrons in their outer shell.
● Physical properties can differ due to different numbers of neutrons.

Question 31

What is the atomic mass number? ★

Answer 31

Total sum of protons and neutrons in an atom of an element.

Question 32

What is an ion? ★

Answer 32

An atom of an element with an overall charge which are formed when atoms gain or lose electrons.

Question 33

What ions do metals/non-metals react to form?

Answer 33

● Metals form positive ions.
● Non-metals form negative ions.

Question 34

What ions do metals/non-metals react to form?

Answer 34

● Metals form positive ions.
● Non-metals form negative ions.

Question 35

Where are electrons arranged in an atom? ★

Answer 35

In energy levels or shells.

Question 36

How many electrons can each shell hold? ★

Answer 36

● 1^st shell can hold 2 electrons.
● 2^nd and 3^rd shell can hold 8 electrons.
● 4^th shell can hold 18 electrons.

Question 37

What determines the way an element reacts?

Answer 37

Amount of electrons in the outermost shell.

Question 38

What is shown in the electronic structure? ★

[example included]

Answer 38

It notes the number of electrons in each shell, separated by commas.

e.g. sodium = 11 electrons so… 2,8,1

Question 39

What is a molecule? ★

Answer 39

Two or more elements held together by a chemical bond (whether the same or different).