AQA AS Level Chemistry Paper 1
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Describe the nuclear model of an atom. [2] -CORRECT ANSWER - Nucleus containing
of protons and neutrons.
- Surrounded by electrons in energy levels.
State the relative mass and charges of a proton [2]. -CORRECT ANSWER Mass: 1
Charge: +1
State the relative mass and charges of a neutron. [2] -CORRECT ANSWER Mass: 1
Charge: 0
Define atomic number (Z). [1] -CORRECT ANSWER The number of protons in an atom.
State the relative mass and charges of an electron. [2] -CORRECT ANSWER Mass:
1/1840
Charge: -1
Define mass number (A). [1] -CORRECT ANSWER The number of protons and
neutrons combined in an atom
Define isotope. [1] -CORRECT 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] -CORRECT
ANSWER -Same chemical properties.
-As same electron configuration.
State the uses of mass spectrometry: [4] -CORRECT ANSWER - Identify elements
- Determine relative molecular mass.
- Determine isotopic mass.
- Determine relative abundance of isotopes.
Why is mass spectrometry done in a vacuum? [1] -CORRECT ANSWER Prevent
positive ions from colliding with molecules in the air.
,Describe electrospray ionization: [4] -CORRECT 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] -CORRECT 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] -CORRECT 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] -CORRECT 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] -CORRECT 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] -CORRECT ANSWER - Each peak
represents different isotope.
- Height gives relative abundance of each isotope.
Give the formula for relative atomic mass: [1] -CORRECT ANSWER (sum of
abundances not 100)
Describe where electrons are found. [3] -CORRECT ANSWER - Found in shells,
orbiting nucleus.
- Within each shell there are sub-shells.
- Within each sub-shell we find orbitals.
Define orbital. [1] -CORRECT 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] -CORRECT ANSWER a) one’s orbital
b) three p orbitals
c) five d orbitals
, Define highest energy electron. [1] -CORRECT ANSWER The outer most electron on
an atom or ion.
What is stated by the Aufbau principle? [1] -CORRECT ANSWER Orbitals of lower
energy are always filled first.
What are the exceptions to the Aufbau principle? [3] -CORRECT ANSWER Cr - 3d5
4s2
Cu - 3d10 4s1
Define ionization energy. [2] -CORRECT ANSWER The amount of energy needed to
remove a mole of electrons from a mole of atoms, in the gaseous state.
Units kJmol-1
Why does ionization energy increase each time? [1] -CORRECT ANSWER The second
electron is removed from an ion that already has a positive charge.
Give the equation for 3rd ionization energy. [1] -CORRECT ANSWER
State 3 factors affecting ionization energy: [3] -CORRECT ANSWER - Atomic Radius
- Nuclear Charge
- Shielding
Explain how atomic radius affects ionization energy. [2] -CORRECT ANSWER - How far
the outer electrons are from the attractive power of the nucleus.
- The further an outer electron from the attractive power of the nucleus, the less energy
is required to ionize it.
Explain how nuclear charge affects ionization energy. [2] -CORRECT ANSWER - How
many protons are attracting the outer electron.
- The greater the nuclear charge, the stronger the attraction to the outer electron, so
more energy is required to ionize it.
Explain how shielding affects ionization energy. [2] -CORRECT ANSWER - How many
electrons are between the nucleus and the outer electron so shielding the attractive
power of the nucleus.
- The more inner electrons there are, the more the nucleus is shielded and the less
energy is required to ionize the outer electron.
Explain the trend in ionization energy down a group [3] -CORRECT ANSWER Ionization
energy decreases going down the group.
- Atomic radius increases
- More shielding
Explain the general trend in ionization energy across Period 3. [3] -CORRECT
ANSWER General increase in IE across Period 3, this is because...
||LATEST EXAM UPDATE WITH
QUESTIONS AND
ANSWERS||STUDY
NOW||ALREADY GRADED A+||
Describe the nuclear model of an atom. [2] -CORRECT ANSWER - Nucleus containing
of protons and neutrons.
- Surrounded by electrons in energy levels.
State the relative mass and charges of a proton [2]. -CORRECT ANSWER Mass: 1
Charge: +1
State the relative mass and charges of a neutron. [2] -CORRECT ANSWER Mass: 1
Charge: 0
Define atomic number (Z). [1] -CORRECT ANSWER The number of protons in an atom.
State the relative mass and charges of an electron. [2] -CORRECT ANSWER Mass:
1/1840
Charge: -1
Define mass number (A). [1] -CORRECT ANSWER The number of protons and
neutrons combined in an atom
Define isotope. [1] -CORRECT 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] -CORRECT
ANSWER -Same chemical properties.
-As same electron configuration.
State the uses of mass spectrometry: [4] -CORRECT ANSWER - Identify elements
- Determine relative molecular mass.
- Determine isotopic mass.
- Determine relative abundance of isotopes.
Why is mass spectrometry done in a vacuum? [1] -CORRECT ANSWER Prevent
positive ions from colliding with molecules in the air.
,Describe electrospray ionization: [4] -CORRECT 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] -CORRECT 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] -CORRECT 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] -CORRECT 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] -CORRECT 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] -CORRECT ANSWER - Each peak
represents different isotope.
- Height gives relative abundance of each isotope.
Give the formula for relative atomic mass: [1] -CORRECT ANSWER (sum of
abundances not 100)
Describe where electrons are found. [3] -CORRECT ANSWER - Found in shells,
orbiting nucleus.
- Within each shell there are sub-shells.
- Within each sub-shell we find orbitals.
Define orbital. [1] -CORRECT 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] -CORRECT ANSWER a) one’s orbital
b) three p orbitals
c) five d orbitals
, Define highest energy electron. [1] -CORRECT ANSWER The outer most electron on
an atom or ion.
What is stated by the Aufbau principle? [1] -CORRECT ANSWER Orbitals of lower
energy are always filled first.
What are the exceptions to the Aufbau principle? [3] -CORRECT ANSWER Cr - 3d5
4s2
Cu - 3d10 4s1
Define ionization energy. [2] -CORRECT ANSWER The amount of energy needed to
remove a mole of electrons from a mole of atoms, in the gaseous state.
Units kJmol-1
Why does ionization energy increase each time? [1] -CORRECT ANSWER The second
electron is removed from an ion that already has a positive charge.
Give the equation for 3rd ionization energy. [1] -CORRECT ANSWER
State 3 factors affecting ionization energy: [3] -CORRECT ANSWER - Atomic Radius
- Nuclear Charge
- Shielding
Explain how atomic radius affects ionization energy. [2] -CORRECT ANSWER - How far
the outer electrons are from the attractive power of the nucleus.
- The further an outer electron from the attractive power of the nucleus, the less energy
is required to ionize it.
Explain how nuclear charge affects ionization energy. [2] -CORRECT ANSWER - How
many protons are attracting the outer electron.
- The greater the nuclear charge, the stronger the attraction to the outer electron, so
more energy is required to ionize it.
Explain how shielding affects ionization energy. [2] -CORRECT ANSWER - How many
electrons are between the nucleus and the outer electron so shielding the attractive
power of the nucleus.
- The more inner electrons there are, the more the nucleus is shielded and the less
energy is required to ionize the outer electron.
Explain the trend in ionization energy down a group [3] -CORRECT ANSWER Ionization
energy decreases going down the group.
- Atomic radius increases
- More shielding
Explain the general trend in ionization energy across Period 3. [3] -CORRECT
ANSWER General increase in IE across Period 3, this is because...
