Module C4: Chemical Patterns
C4.1 What are the patterns in the properties of elements?
1. understand that atoms of each element have different proton numbers
2. understand that arranging the elements in order of their proton
numbers gives repeating
patterns in the properties of elements
3. understand that early attempts to find connections between the
chemical properties of the
elements and their relative atomic mass were dismissed by the
scientific community
4. recall the significant stages in the history of the development of
the Periodic Table to include
the ideas of Döbereiner, Newlands and Mendeleev
5. understand how Mendeleev used his Periodic Table to predict the
existence of unknown
elements
6. use the Periodic Table to obtain the names, symbols, relative atomic
masses and proton
numbers of elements
7. understand that a group of elements is a vertical column in the
Periodic Table and that the
elements in a group have similar properties
8. recall that a period is a row of elements in the Periodic Table
9. use the Periodic Table to classify an element as a metal or
non-metal
10. use patterns in the Periodic Table to interpret data and predict
properties of elements
Candidates
will be given a copy of the Periodic Table with the examination paper
11. recall and recognise the chemical symbols for the Group 1 metals
(also known as the alkali
metals) lithium, sodium and potassium
12. recall that the alkali metals are shiny when freshly cut but
tarnish rapidly in moist air due to
reaction with oxygen
13. use qualitative and quantitative data to identify patterns and make
predictions about the
properties of Group 1 metals (for example, melting point, boiling
point, density, formulae of
compounds and relative reactivity)
14. describe the reactions of lithium, sodium and potassium with cold
water
15. recall that alkali metals react with water to form hydrogen and an
alkaline solution of a
hydroxide with the formula MOH
16. recall that alkali metals react vigorously with chlorine to form
colourless, crystalline salts with
the formula MCl
17. understand and give examples to show that the alkali metals become
more reactive as the
group is descended
18. recall the main hazard symbols and be able to give the safety
precautions for handling
hazardous chemicals (limited to explosive, toxic, corrosive, oxidizing,
and highly flammable)
19. state and explain the precautions necessary when working with Group
1 metals and alkalis
20. recall and recognise the chemical symbols for the atoms of the
Group 7 elements (also
known as the halogens) chlorine, bromine and iodine
21. recall the states of these halogens at room temperature and
pressure
22. recall the colours of these halogens in their normal physical state
at room temperature and
as gases
23. recall that the halogens consist of diatomic molecules
24. use qualitative and quantitative data to identify patterns and make
predictions about the
properties of the Group 7 elements (for example melting point, boiling
point, formulae of
compounds and relative reactivity)
25. understand that the halogens become less reactive as the group is
descended and give
examples to show this
26. understand how a trend in reactivity for halogens can be shown by
their displacement
reactions and by their reactions with alkali metals and with iron
27. state and explain the safety precautions necessary when working
with the halogens
28. recall the formulae of:
a. hydrogen, water
and halogen (limited to chlorine, bromine and iodine) molecules
b. the chlorides,
bromides and iodides (halides) of Group 1 metals (limited to lithium,
sodium and
potassium)
29. write word equations for reactions of alkali metals and halogens in
this module and for other
reactions when given appropriate information
30. interpret symbol equations, including the number of atoms of each
element, the number
of molecules of each element or covalent compound and the number of
‘formulas’ of ionic
compounds, in reactants and products
In this
context, ‘formula’ is used in the case of ionic compounds as an equivalent
to molecules in covalent
compounds; the concept of the mole is not covered in the
specification
31. balance unbalanced symbol equations
32. write balanced equations, including the state symbols (s), (g), (l
) and (aq), for
reactions of alkali metals and halogens in this module and for other
reactions when
given appropriate information
33. recall the state symbols (s), (l ), (g) and (aq) and understand
their use in equations.
C4.2 How do chemists explain the patterns in the properties of
elements?
1. describe the structure of an atom in terms of protons and neutrons
in a very small central
nucleus with electrons arranged in shells around the nucleus
2. recall the relative masses and charges of protons, neutrons and
electrons
3. understand that in any atom the number of electrons equals the
number of protons
4. understand that all the atoms of the same element have the same
number of protons
5. understand that the elements in the Periodic Table are arranged in
order of proton number
6. recall that some elements emit distinctive flame colours when heated
(for example lithium,
sodium and potassium)
Recall of
specific flame colours emitted by these elements is not required
7. understand that the light emitted from a particular element gives a
characteristic line
spectrum
8. understand that the study of spectra has helped chemists to discover
new elements
9. understand that the discovery of some elements depended on the
development of new
practical techniques (for example spectroscopy)
10. use the Periodic Table to work out the number of protons, electrons
and neutrons in
an atom
11. use simple conventions, such as 2.8.1 and dots in circles, to
represent the electron
arrangements in the atoms of the first 20 elements in the Periodic
Table, when the number of
electrons or protons in the atom is given (or can be derived from the
Periodic Table)
12. understand that a shell (or energy level) fills with electrons
across a period
13. understand that elements in the same group have the same number of
electrons in their
outer shell and how this relates to group number
14. understand that the chemical properties of an element are
determined by its electron
arrangement, illustrated by the electron configurations of the atoms of
elements in
Groups 1 and 7.
C4.3 How do chemists explain the properties of compounds of Group 1 and
Group 7
elements?
1. understand that molten compounds of metals with non-metals conduct
electricity and that
this is evidence that they are made up of charged particles called ions
2. understand that an ion is an atom (or group of atoms) that has
gained or lost electrons and
so has an overall charge
3. account for the charge on the ions of Group 1 and Group 7 elements
by comparing the
number and arrangement of the electrons in the atoms and ions of these
elements
4. work out the formulae of ionic compounds given the charges on the
ions
5. work out the charge on one ion given the formula of a salt and the
charge on the other
ion
6. recall that compounds of Group 1 metals with Group 7 elements are
ionic
7. understand that solid ionic compounds form crystals because the ions
are arranged in a
regular lattice
8. describe what happens to the ions when an ionic crystal melts or
dissolves in water
9. explain that ionic compounds conduct electricity when molten or when
dissolved in water
because the ions are charged and they are able to move around
independently in the liquid.
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