Edexcel Chemistry A level Paper 3
Comprehensive 2024Exam Quiz Study
Guide
Structure of an atom - Answer>>An atom has a nucleus
containing protons and neutrons that is surrounded by orbiting
electrons.
Protons - Answer>>have a relative charge of +1 and a relative
mass of 1
Neutrons - Answer>>have a relative charge of 0 and a relative
mass of 1
Electrons - Answer>>have a relative charge of -1 and a relative
mass of 1/1840
Atomic Number - Answer>>*The number of protons in an atom.
An atom will have the same number of electrons*
Mass number - Answer>>*The number of protons and neutrons
in an atom*
Isotope - Answer>>*Atoms of the same element with different
masses due to differing numbers of neutrons*
Relative atomic mass - Answer>>*The weighted mean mass of
an atom of an element compared to the mass of one-twelfth of an
atom of carbon¹²*
Relative Isotopic Mass - Answer>>*The mass of an atom of an
isotope of an element compared to one twelfth the mass of an
atom of carbon¹²*
,Relative Molecular Mass and Relative Formula Mass -
Answer>>Relative molecular mass is the mass of a molecule,
relative formula mass is used for ions (or compounds with giant
structures)
Calculating relative molecular mass - Answer>>Add up the
masses multiplied by their frequency and then divide the answer
by the total frequency
Mass Spectra - Answer>>Mass Spectra will show the masses
and how frequently they occur, either as a number of a
percentage. This can be used to calculate the relative atomic
mass of an element.
Diatomic molecules such as chlorine have 3 large peaks at the
end due to the 3 possible combinations of isotopes.
The mass spectrum of a molecule ends in a large molecular ion
peak that gives the relative molecular mass for the molecule
First ionisation energy - Answer>>*The energy required to
remove one mole of ions from one mole of gaseous atoms to form
one mole of unipositive atoms*
Second ionisation energy - Answer>>*The amount of energy
required to remove one mole of electrons from one mole of
unipositive ions to form one mole of 2+ ions*
Trends in ionisation energies - Answer>>Ionisation energy
decreases down the group as although the nuclear charge
increases (thereby attracting the electrons more) there are more
quantum shells shielding the outer electron from the nucleus and
the outer electron is further from the nucleus, thus inhabiting a
higher energy quantum shell
,Subshells - Answer>>Quantum shells are made up of
subshells.
There are s, p and d subshells
Orbitals - Answer>>orbitals make up subshells, each one can
contain 2 electrons
s subshell - Answer>>Shaped like a sphere with one orbital
(hence contains 2 electrons)
p subshell - Answer>>Shaped like 3 dumbbells at right angles
to each other. Has 3 orbitals and thus 6 electrons
d subshell - Answer>>Has 5 orbitals and thus 10 electrons
Electron configuration - Answer>>This determines an elements
chemical properties
Hund's rule - Answer>>Electrons will occupy the orbitals singly
before pairing takes place
Aufbau Principle - Answer>>Electrons will fill lower energy
subshells first (hence they fill 4s subshell before the 3 subshell)
Pauli exclusion principle - Answer>>For electrons to occupy the
same orbital they must have an opposite spin
Exceptions to electron configuration - Answer>>Chromium and
Copper are exceptions to the pattern. This is because for both
cases the 3d subshell is either one electron away from being half
full or completely full. As these states are more stable they pull an
electron down from the 4s subshell.
, Additionally, when transition metals ionise they lose the electrons
in the 4s subshell first, despite gaining electrons in the 3d
subshell last.
Periodicity - Answer>>*The repeating of patterns across
different periods*
s, p and d blocks - Answer>>
Evidence for electron configuration - Answer>>Evidence for
electron configuration can be found from:
- Atomic emission spectra
-Successive ionisation energies
-First ionisation energies of successive elements
Atomic emission spectra - Answer>>When atoms absorb
energy (either heat or electrical) the electrons are exited and
move up a quantum level before returning to the ground state.
The energy is released as electromagnetic radiation. The spectra
of this radiation is unique for every atom, as it requires differing
amounts of energy to excite electrons of different atoms because
there are only specific quantum shells that they can go to.
Otherwise the frequency would be continuous.
Successive ionisation energies - Answer>>The jumps show
where an electron is in a new quantum shell and so requires more
energy to be removed.
This can be used to determine which group the element is in
First ionisation energies of successive elements - Answer>>The
dips are where a new quantum shell or sub shell provides extra
shielding and even where all of the orbitals have one electron. All
factors that make removing the outer electron easier.
This provides evidence for the existence of subshells
Comprehensive 2024Exam Quiz Study
Guide
Structure of an atom - Answer>>An atom has a nucleus
containing protons and neutrons that is surrounded by orbiting
electrons.
Protons - Answer>>have a relative charge of +1 and a relative
mass of 1
Neutrons - Answer>>have a relative charge of 0 and a relative
mass of 1
Electrons - Answer>>have a relative charge of -1 and a relative
mass of 1/1840
Atomic Number - Answer>>*The number of protons in an atom.
An atom will have the same number of electrons*
Mass number - Answer>>*The number of protons and neutrons
in an atom*
Isotope - Answer>>*Atoms of the same element with different
masses due to differing numbers of neutrons*
Relative atomic mass - Answer>>*The weighted mean mass of
an atom of an element compared to the mass of one-twelfth of an
atom of carbon¹²*
Relative Isotopic Mass - Answer>>*The mass of an atom of an
isotope of an element compared to one twelfth the mass of an
atom of carbon¹²*
,Relative Molecular Mass and Relative Formula Mass -
Answer>>Relative molecular mass is the mass of a molecule,
relative formula mass is used for ions (or compounds with giant
structures)
Calculating relative molecular mass - Answer>>Add up the
masses multiplied by their frequency and then divide the answer
by the total frequency
Mass Spectra - Answer>>Mass Spectra will show the masses
and how frequently they occur, either as a number of a
percentage. This can be used to calculate the relative atomic
mass of an element.
Diatomic molecules such as chlorine have 3 large peaks at the
end due to the 3 possible combinations of isotopes.
The mass spectrum of a molecule ends in a large molecular ion
peak that gives the relative molecular mass for the molecule
First ionisation energy - Answer>>*The energy required to
remove one mole of ions from one mole of gaseous atoms to form
one mole of unipositive atoms*
Second ionisation energy - Answer>>*The amount of energy
required to remove one mole of electrons from one mole of
unipositive ions to form one mole of 2+ ions*
Trends in ionisation energies - Answer>>Ionisation energy
decreases down the group as although the nuclear charge
increases (thereby attracting the electrons more) there are more
quantum shells shielding the outer electron from the nucleus and
the outer electron is further from the nucleus, thus inhabiting a
higher energy quantum shell
,Subshells - Answer>>Quantum shells are made up of
subshells.
There are s, p and d subshells
Orbitals - Answer>>orbitals make up subshells, each one can
contain 2 electrons
s subshell - Answer>>Shaped like a sphere with one orbital
(hence contains 2 electrons)
p subshell - Answer>>Shaped like 3 dumbbells at right angles
to each other. Has 3 orbitals and thus 6 electrons
d subshell - Answer>>Has 5 orbitals and thus 10 electrons
Electron configuration - Answer>>This determines an elements
chemical properties
Hund's rule - Answer>>Electrons will occupy the orbitals singly
before pairing takes place
Aufbau Principle - Answer>>Electrons will fill lower energy
subshells first (hence they fill 4s subshell before the 3 subshell)
Pauli exclusion principle - Answer>>For electrons to occupy the
same orbital they must have an opposite spin
Exceptions to electron configuration - Answer>>Chromium and
Copper are exceptions to the pattern. This is because for both
cases the 3d subshell is either one electron away from being half
full or completely full. As these states are more stable they pull an
electron down from the 4s subshell.
, Additionally, when transition metals ionise they lose the electrons
in the 4s subshell first, despite gaining electrons in the 3d
subshell last.
Periodicity - Answer>>*The repeating of patterns across
different periods*
s, p and d blocks - Answer>>
Evidence for electron configuration - Answer>>Evidence for
electron configuration can be found from:
- Atomic emission spectra
-Successive ionisation energies
-First ionisation energies of successive elements
Atomic emission spectra - Answer>>When atoms absorb
energy (either heat or electrical) the electrons are exited and
move up a quantum level before returning to the ground state.
The energy is released as electromagnetic radiation. The spectra
of this radiation is unique for every atom, as it requires differing
amounts of energy to excite electrons of different atoms because
there are only specific quantum shells that they can go to.
Otherwise the frequency would be continuous.
Successive ionisation energies - Answer>>The jumps show
where an electron is in a new quantum shell and so requires more
energy to be removed.
This can be used to determine which group the element is in
First ionisation energies of successive elements - Answer>>The
dips are where a new quantum shell or sub shell provides extra
shielding and even where all of the orbitals have one electron. All
factors that make removing the outer electron easier.
This provides evidence for the existence of subshells
