AQA AS CHEMISTRY ACTUAL EXAM PAPER
2026 QUESTIONS WITH SOLUTIONS GRADED
A+
◉ State the relative mass and charges of a proton [2]. Answer: Mass:
1
Charge: +1
◉ State the relative mass and charges of a neutron. [2] Answer:
Mass: 1
Charge: 0
◉ Define atomic number (Z). [1] Answer: The number of protons in
an atom.
◉ State the relative mass and charges of an electron. [2] Answer:
Mass: 1/1840
Charge: -1
◉ Define mass number (A). [1] Answer: The number of protons and
neutrons combined in an atom
,◉ Define isotope. [1] Answer: Atoms with the same number of
protons but a different number of neutrons.
◉ Describe the chemical properties of two isotopes of the same
element. [2] Answer: -Same chemical properties.
-As same electron configuration.
◉ State the uses of mass spectrometry: [4] Answer: - Identify
elements
- Determine relative molecular mass.
- Determine isotopic mass.
- Determine relative abundance of isotopes.
◉ Why is mass spectrometry done in a vacuum? [1] Answer: Prevent
positive ions from colliding with molecules in the air.
◉ Describe electrospray ionisation: [4] Answer: - Sample dissolved
in volatile solvent.
- Injected through a fine hypodermic needle giving a fine
mist/aerosol.
- Tip of needle connected to positive terminal of a high voltage.
- Each molecule gains a proton as it leaves the needle.
,◉ Describe acceleration: [2] Answer: - The positive ions are
attracted to a negatively charged plate and accelerate towards it.
- All ions accelerate forward so that they have the same kinetic
energy, but reach different velocities due to their varying masses.
(lighter → faster)
◉ Describe ion drift: [2] Answer: - Some of the ions pass through a
hole in the negatively charged plate, forming a beam of particles.
They travel along the 'flight tube' towards the detector.
- As the ions are travelling at different speeds, they drift apart
further.
◉ Describe detection: [2] Answer: - When the positive ions hit the
negatively charged detection plate, they gain an electron.
- This generates a current, the size of which is proportional to the
number of each type of ion.
◉ Describe data analysis: [1] Answer: The signal from the detector is
passed to a computer which generates a mass spectrum from the
current.
◉ What does each peak on the graph represent? [2] Answer: - Each
peak represents different isotope.
- Height gives relative abundance of each isotope.
, ◉ Give the formula for relative atomic mass: [1] Answer: (sum of
abundances not 100)
◉ Describe where electrons are found. [3] Answer: - Found in shells,
orbiting nucleus.
- Within each shell there are sub-shells.
- Within each sub-shell we find orbitals.
◉ Define orbital. [1] Answer: An orbital is a region within an atom
that can hold up to two electrons with opposite spins.
◉ How many orbitals are there in...
a) an s sub-shell
b) a p sub-shell
c) a d sub-shell [3] Answer: a) one s orbital
b) three p orbitals
c) five d orbitals
◉ Define highest energy electron. [1] Answer: The outer most
electron on an atom or ion.
◉ What is stated by the Aufbau principle? [1] Answer: Orbitals of
lower energy are always filled first.
2026 QUESTIONS WITH SOLUTIONS GRADED
A+
◉ State the relative mass and charges of a proton [2]. Answer: Mass:
1
Charge: +1
◉ State the relative mass and charges of a neutron. [2] Answer:
Mass: 1
Charge: 0
◉ Define atomic number (Z). [1] Answer: The number of protons in
an atom.
◉ State the relative mass and charges of an electron. [2] Answer:
Mass: 1/1840
Charge: -1
◉ Define mass number (A). [1] Answer: The number of protons and
neutrons combined in an atom
,◉ Define isotope. [1] Answer: Atoms with the same number of
protons but a different number of neutrons.
◉ Describe the chemical properties of two isotopes of the same
element. [2] Answer: -Same chemical properties.
-As same electron configuration.
◉ State the uses of mass spectrometry: [4] Answer: - Identify
elements
- Determine relative molecular mass.
- Determine isotopic mass.
- Determine relative abundance of isotopes.
◉ Why is mass spectrometry done in a vacuum? [1] Answer: Prevent
positive ions from colliding with molecules in the air.
◉ Describe electrospray ionisation: [4] Answer: - Sample dissolved
in volatile solvent.
- Injected through a fine hypodermic needle giving a fine
mist/aerosol.
- Tip of needle connected to positive terminal of a high voltage.
- Each molecule gains a proton as it leaves the needle.
,◉ Describe acceleration: [2] Answer: - The positive ions are
attracted to a negatively charged plate and accelerate towards it.
- All ions accelerate forward so that they have the same kinetic
energy, but reach different velocities due to their varying masses.
(lighter → faster)
◉ Describe ion drift: [2] Answer: - Some of the ions pass through a
hole in the negatively charged plate, forming a beam of particles.
They travel along the 'flight tube' towards the detector.
- As the ions are travelling at different speeds, they drift apart
further.
◉ Describe detection: [2] Answer: - When the positive ions hit the
negatively charged detection plate, they gain an electron.
- This generates a current, the size of which is proportional to the
number of each type of ion.
◉ Describe data analysis: [1] Answer: The signal from the detector is
passed to a computer which generates a mass spectrum from the
current.
◉ What does each peak on the graph represent? [2] Answer: - Each
peak represents different isotope.
- Height gives relative abundance of each isotope.
, ◉ Give the formula for relative atomic mass: [1] Answer: (sum of
abundances not 100)
◉ Describe where electrons are found. [3] Answer: - Found in shells,
orbiting nucleus.
- Within each shell there are sub-shells.
- Within each sub-shell we find orbitals.
◉ Define orbital. [1] Answer: An orbital is a region within an atom
that can hold up to two electrons with opposite spins.
◉ How many orbitals are there in...
a) an s sub-shell
b) a p sub-shell
c) a d sub-shell [3] Answer: a) one s orbital
b) three p orbitals
c) five d orbitals
◉ Define highest energy electron. [1] Answer: The outer most
electron on an atom or ion.
◉ What is stated by the Aufbau principle? [1] Answer: Orbitals of
lower energy are always filled first.
