AQA GCSE

Notes and Questions

Atomic structure and the

periodic table
Atoms, Elements and Compounds:
All substances are made up of a_______. An a______ being the
smallest part of an e_________ that can exist.

1. Define and element:

Every e__________ is represented by a chemical s__________.

Element Symbol
Sodium
Chlorine
Oxygen
K
Si
S
Phosphorous
Compounds:

Compounds are formed when _________ combine through a

chemical ________. The compound contains a ________ proportion
and this can be represented using a _________.

Compounds can only be separated into e________ by

c________ r_________.

When a mixture of iron and sulphur is heated the iron and

sulphur ______ together to produce iron (II) sulphide

The formulae of iron (II) sulphide can be worked out from the
charges.

1) Symbol Fe S
2) Charges 2 2
3) Simplest Ratio 1 1
4) Formulae FeS

5) If the charges are different then reverse the numbers in

step 4.

Al O
3 2
2 3
Al2O3
Using the following table of common elements and their charges to
complete the following formulae:

Element +ve charge Element -ve charge

Sodium (Na) 1 Chloride (Cl) 1
Potassium (K) 1 Bromide (Br) 1
Magnesium (Mg) 2 Oxide (O) 2
Calcium (Ca) 2 Sulphide (S) 2
Aluminium (Al) 3 Nitride (N) 3
Iron (II) (Fe) 2 Nitrate (NO3) 1
Iron (III) (Fe) 3 Hydroxide (OH) 1
Copper (II) (Cu) 2 Sulphate (SO4) 2
Zinc (Zn) 2 Carbonate (CO3) 2
Ammonium (NH4) 1

a) Sodium Bromide

b) Potassium Oxide

c) Iron (III) Chloride

d) Magnesium Nitrate

e) Zinc Hydroxide

f) Ammonium Sulphate
When a reaction occurs we can write equations in the following form.

Reactants  Products

For instance when Iron and Sulphur react the word equation and
symbol equation would be would be:

Iron + Sulphur  Iron (II) Sulphide

Fe + S  FeS

In the example above the equation is said to be balanced

however, more often than not, the symbol equation is not
_________. To be balanced there must be as many of each type on
the left hand side as there is on the right.

e.g. A + B2  AB

Balanced 2A + B2  2AB

The key to balancing equations is to first ensure that you write a

word equation and then fill in the formulae of the various species.
Once this is done they can not be changed.
Try balancing the following reactions (NB do not change the
formulae):

i) A2 + B2  AB

ii) A + B  A2B3

iii) A + B2  AB3

iv) A2 + B2  AB2

v) A2 + B2  A2B3

Write a balanced symbol equation for the following reactions:

a) Sodium + Water  Sodium Hydroxide + Hydrogen

b) Iron + Oxygen  Iron (III) Oxide

Mixtures:

A mixture consists of t____ or more e_________ or c_________

not c_________ combined. The chemical properties of each
substance in the mixture are u____________.

Mixtures can be s___________ by p_________ processes.

Examples include F__________, C_____________, Simple
D_____________, F____________ D___________ and
C__________________.

2. Draw and label the apparatus used for filtration:

3. What does crystallisation involve:

4. What physical property does both types of Distillation

rely on to separate the substances
Separating Mixtures:

1) Chromatography:

Used to separate mixtures of things with different

________.
i) Draw a line on the chromatography paper in
_______.

ii) _____ the dyes on the line.

iii) Pour water or another suitable ______ (e.g.

ethanol) into a beaker ensuring the level is below the
line.

iv) Place the chromatography paper into the water.

v) Allow to develop for five minutes or until the

s______ has nearly reached the top.

vi) Remove the paper and allow to d____ before

comparing the distance travelled by the dyes.

A chromatogram can be used to identify different substances

because under the same conditions the same dyes will travel the same

d__________.
 2) Distillation:

Distillation is used to separate a mixture that contains two or more

substances that have distinctly different _______ _______.

E.g. salt and ______.

Fractional distillation can be used to separate complex mixtures such

as c________ o____ or e_______ and w________.

3) Filtration and Evaporation (Crystallisation):

Some mixtures contain a soluble substance and an insoluble

substance (e.g salt and sand). These mixtures can be separated by:

i) Add the mixture to a suitable _______.

ii) Stir the ______ until one substance has completely

__________.

iii) ______ the mixture and leave the filter paper to dry
(Sand).

Pour the ______ into an evaporating basin and allow the solvent to
________ (Salt).
What separation technique would you use to separate the following
mixtures:

Mixture Technique

Sand and Water

Inks

Ethanol and Water

Air

Copper sulphate and water (to

obtain the Copper Sulphate)

Copper sulphate and water (to

obtain the Water)

Crude Oil

Sugar and Ethanol (to obtain the

Ethanol)

Sugar and Ethanol (to obtain the

Sugar)

Food colourings
Scientific Models of the Atom:

Before the discovery of the e_______, a______ were thought to be

tiny s________ that could not be d________.

The discovery of the e_________ by J.J. Thomson led to the

p_____ p__________ model of the a____.

5. Describe the plum pudding model:

6. What would happen if the Plum Pudding was

bombarded with alpha particles?:
In fact Rutherford and Marsden found that the alpha particles were
s___________.

7. How did this new evidence lead to a change in theory:

The new model was called the n________ model. It was further

adapted by Niels B_______ who suggested that e__________ orbit

the n______ at specific d________. This was readily accepted

because both his t__________ calculations and his e___________

observations agreed.

Later experiments led to the idea that the p________ charge of any

n________ could be s__________ into a whole number of smaller

p__________, each p_________ having the same amount of

p___________ charge.

8. What name was given to these particles?

In 1932 James C_____________ carried out the experiment above.

This experiment showed the existence of another particle in the

n________, he called it a n___________. This was about 20 years

after the n_______ became and a_________ s___________ idea.

Atoms:

Atoms have a small central __________, which is made up of

_________ and ________ and around which there
are___________ which are o___________ in s_________.
Atoms are v________ s______ and typically have a radius of a
about _________. The radius of the n_________ is about
__________ smaller than the atom but it contains almost all of the
m____________

Name of Particle Relative Mass Relative Charge

The Atomic (Proton Number) tells us the number of

p______ in an atom which also happens to be the number of
e_______.

When some atoms r________ they l_________ or

g_________ e_________. In this case the number of p________
and e___________ are not e________ and therefore the atom is
now c_________. We call a c_________ atom an I_____.

9. How do you calculate the number of electrons in an

ion?
The Mass Number tells us the total number of p_____ and n______.
Therefore to calculate the number of n_______:

10. How do you calculate the number of neutrons in an

atom?

e.g. For Sodium:

Mass No. = 23

Atomic No. = 11

Therefore No. of Neutrons = 23 -11

= 12
 Using your Periodic Table complete the following table.

Element Atomic No. Mass No. Protons Electrons Neutrons

C 6 6

19
F 9

25
Mg 12

35
Cl 35

Ca 20

238
U 238

7
Li+

27
Al3+

16
O2-
Isotopes are atoms of the same ______ which have the same number

of ______ but different number of ______. The Relative ______

Mass must be calculated from the _________ and Relative Isotopic

Mass of every isotope.

Relative Atomic Mass (Ar): the _______ mass of 1 ______ of

atoms relative to 1/12 the mass of 1 mole carbon-12 _____.

RAM = Sum of (Isotopic Mass x % Abundance)

100

10. For Boron there are two isotopes with their abundances
in the brackets. Calculate the Relative Atomic Mass.

10.0 (18.7%) 11.0 (81.3%)

10.8

11. For Neon there are three isotopes with their abundances
in the brackets. Calculate the Relative Atomic Mass.

20.0 (90.9%) 21.0 (0.3%) 22.0 (8.8%)

20.2
Electron Configuration:

The electrons orbit the nucleus. The electrons are arranged in shells
that represent orbit of similar energy.

1st Shell: Max 2 electrons

2nd Shell: Max 8 electrons

3rd Shell: Max 8 electrons

4th Shell: The remainder if any

e.g. Sodium- 11 Electrons

Therefore: 1st Shell: 2

2nd Shell: 8

3rd Shell: 1

Overall: 2, 8, 1

Workout the electron configurations for the following elements:

i) Carbon

ii) Magnesium

iii) Potassium
Electron Configurations can also be drawn:

e.g. Sodium

Draw electron configurations for the following:

i) Oxygen

ii) Chlorine

iii) Calcium

a) What is the relationship between the group number and the number of
outer electrons.
The Periodic Table

The e___________ in the Periodic Table are arranged in order of

a_________ n___________. Elements with s_________
c________ properties are in columns (known as g_______). The
table is called a periodic table because s________ properties occur
at r_________ intervals.

12. Why do Lithium, Sodium and Potassium have similar

properties?

The position of an element in the Periodic Table therefore is

determined by the n________ of o________ e_________ and the
number of e_________ s__________ the element has.

13. Which element has 4 outer electrons and 3 shells?

14. Which element has 6 outer electrons and 2 shells?

15. How many outer electrons and shells does Calcium have?
Before the discovery of p_________, n_______ and e_________,
scientists attempted to classify the elements by arranging them in
order of their a_________ w________.

16. What are some of the issues with Newland’s table

above, from the 1863

To overcome some of these problems a Russian scientist called

D__________ M_____________ created his own Periodic Table
but left g_______ for e__________ that had yet to be
d__________. He also changed the order of some e_________
which had been based upon a________ w_______.
After M________ death various e___________ were discovered
that filled the g____ and they had very similar p_______ to those
he had suggested.

17. Give an example of one such element?

Knowledge of I_________ made it possible to explain why the order

based on a_________ w_________ was not always correct.

One of the largest changes that followed was the identification of a

whole g______ of e__________. They had long gone undiscovered
because they were i_______ and so did not r________ with
anything. They were known as the N________ G_______.
H________ the first was discovered in 1868.
Metals are found on the l____ and non-metals are found on the

r________. The classification of an element as either a metal or

non-metal depends upon:

i) M_______ are elements that r________ to form

p___________ ions. N__________ are elements that

r__________ to form n_________ ions.

ii) The e___________conductivity of the element. All metals

are good c____________ because of their delocalised

e___________. Non-metals are insulators because their

shared e___________ are not free to move. The exception

to the rule is g___________.

iii) The acid-base nature of their oxides. Metals react with

oxygen to form b________ oxides. Non-metals react with

oxygen to form a_________ oxides.

18. Why do metals form positive ions and non-metals form

negative ions?
Group 0 (Noble Gases)

This group includes the elements H__________, N_______,

A________ among others.

They are referred to as the Noble Gases because they are

u_________ and do not easily form m___________.

19. Explain why they do not react?

20. Give the electron configuration of He, Ne and Ar?

21. Describe and explain the trend in Boiling Points of

Group 0?
Group 1:

The alkali metals all react v____________ with w_______,

o________ and c__________ because they only have to l______

one electron.

22. Describe the reaction of sodium with water?

a) Write a balanced equation for this reaction?

23. Describe the reaction of lithium with oxygen?

24. Describe the reaction of potassium with chlorine?

As we go down the group the metals become more re________

because the outer e_________ is further from the n________ so
there is a weaker a__________, so less e________ is required to
remove it.
Group 7 (The Halogens):

Fill in the table of their properties:

Halogen Formula Colour State at room

temperature
Fluorine
Chlorine
Bromine
Iodine
Astatine

The halogens all react in a similar way because they are trying to
g_____ an electron into their outer s_______.

As you go down the group the outer s________ is further from the
n_________ and therefore the a________ is weaker. This means it
is h________to g______ an electron.

This means that a more r_______ halogen will take an e________

from the halide (n__________ ion) of a less r_______ halogen and
thereby d_________ it from the solution.

The reactions are examples of r_____ reactions. This is because the

halogen is r________ and the halide ion is o_________.

e.g. Chlorine + Iodide Chloride + Iodine

Cl2 + 2e- 2Cl-

2I- I2 + 2e-

Cl2 + 2I- 2Cl- + I2

Write word equations and where appropriate symbol equations for
the following:

25. Chlorine + Potassium Bromide 

26. Bromine + Potassium Iodide 

27. Iodine + Potassium Chloride 

28. Chlorine + Potassium Iodide 

Transition Metals

The transition metals are found in the m_______ of the Periodic

Table. They have s_________ properties but these are different to
those of metals in g_______ 1.

29. How do the melting points of transition metals differ to

those of group 1?

30. How does the hardness of transition metals differ to those

of group 1?

31. How do the reactivity of transition metals differ to those of

group 1?
 32. How does the density of transition metals differ to those of
group 1?

Many transition metals also have i______ with different c_______.

They often form compounds which are c____________ and are very
useful as c___________.

33. Give examples of transition metals ions for the following

metals:

Cr
Mn
Fe
Co
Ni
Cu
34. What are the colours of these transition metal compounds:

K2Cr2O7

KMnO4

Fe2O3

CoCl2

NiO

CuSO4

35. Complete the table about transition metal catalysts:

Catalyst Name Process or Reaction

MnO2

Fe

Ni

V2O5

Pt / Rh