Key ideas
Monday, May 5, 2025 12:39 PM
The complex and diverse phenomena of the natural world can be described in terms of a small number of universal, key ideas
in chemistry:
Some of these ideas you need to get your head round are:
They underpin many aspects of the science assessment and will therefore be assessed across all papers.
• matter is composed of tiny particles called atoms and there are about 100 different naturally occurring types of atoms
called elements
○ Found on the periodic table
• elements show periodic relationships in their chemical and physical properties
• these periodic properties can be explained in terms of the atomic structure of the elements
○ e.g. number of electron shells
• atoms bond by either transferring electrons from one atom to another or by sharing electrons
○ Ionic/covalent/metallic bonding
• the shapes of molecules (groups of atoms bonded together) and the way giant structures are arranged is of great
importance in terms of the way they behave
○ Giant ionic lattice
• there are barriers to reaction so reactions occur at different rates
○ Temperature, internal energy
• chemical reactions take place in only three different ways:
• proton transfer
• electron transfer
• electron sharing
• energy is conserved in chemical reactions so can therefore be neither created or destroyed.
○ Conservation of mass
Introduction Page 1
,Fundamental concepts
Monday, May 5, 2025 12:39 PM
Introduction Page 2
,Working scientifically
Monday, May 5, 2025 12:39 PM
Accurate An accurate measurement is one that is close
to the true value.
Precise Measurements are precise if they cluster closely
Repeatable Measurements are repeatable when repetition under the same
conditions by the same investigator gives similar results
Reproducibl Measurements are reproducible if similar results are obtained
e by different investigators
Random Due to results varying in unpredictable ways. Can be reduced by
error making more measurements and reporting a mean value
Systematic Measurement results differ from the true value by a consistent
error amount each time
Anomalous Should be examined to try to identify the cause and, if a product
results of a poor measurement, ignored.
Multiple Size Power of ten (x10²) Prefix Prefix abbreviation
1,000,000,000,000 12 tera- T
1,000,000,000 9 giga- G
1,000,000 6 mega- M
1,000 3 kilo- k
0.01 -2 centi- c
0.001 -3 milli- m
0.000001 -6 micro- μ
0.000000001 -9 nano- n
Mass: 1g = 1000 mg
Use IUPAC chemical nomenclature:
Introduction Page 3
,
Introduction Page 4
Monday, May 5, 2025 12:39 PM
The complex and diverse phenomena of the natural world can be described in terms of a small number of universal, key ideas
in chemistry:
Some of these ideas you need to get your head round are:
They underpin many aspects of the science assessment and will therefore be assessed across all papers.
• matter is composed of tiny particles called atoms and there are about 100 different naturally occurring types of atoms
called elements
○ Found on the periodic table
• elements show periodic relationships in their chemical and physical properties
• these periodic properties can be explained in terms of the atomic structure of the elements
○ e.g. number of electron shells
• atoms bond by either transferring electrons from one atom to another or by sharing electrons
○ Ionic/covalent/metallic bonding
• the shapes of molecules (groups of atoms bonded together) and the way giant structures are arranged is of great
importance in terms of the way they behave
○ Giant ionic lattice
• there are barriers to reaction so reactions occur at different rates
○ Temperature, internal energy
• chemical reactions take place in only three different ways:
• proton transfer
• electron transfer
• electron sharing
• energy is conserved in chemical reactions so can therefore be neither created or destroyed.
○ Conservation of mass
Introduction Page 1
,Fundamental concepts
Monday, May 5, 2025 12:39 PM
Introduction Page 2
,Working scientifically
Monday, May 5, 2025 12:39 PM
Accurate An accurate measurement is one that is close
to the true value.
Precise Measurements are precise if they cluster closely
Repeatable Measurements are repeatable when repetition under the same
conditions by the same investigator gives similar results
Reproducibl Measurements are reproducible if similar results are obtained
e by different investigators
Random Due to results varying in unpredictable ways. Can be reduced by
error making more measurements and reporting a mean value
Systematic Measurement results differ from the true value by a consistent
error amount each time
Anomalous Should be examined to try to identify the cause and, if a product
results of a poor measurement, ignored.
Multiple Size Power of ten (x10²) Prefix Prefix abbreviation
1,000,000,000,000 12 tera- T
1,000,000,000 9 giga- G
1,000,000 6 mega- M
1,000 3 kilo- k
0.01 -2 centi- c
0.001 -3 milli- m
0.000001 -6 micro- μ
0.000000001 -9 nano- n
Mass: 1g = 1000 mg
Use IUPAC chemical nomenclature:
Introduction Page 3
,
Introduction Page 4
