A-Level Edexcel Chemistry Exam
Questions & Answers 2023/2024
how to test for C=C - ANSWER-decolourises bromine water
Atomic Number - ANSWER-number of protons in the nucleus of an atom of that element.
Mass Number - ANSWER-the sum of protons and neutrons in a nuclues of an atom
Isotopes - ANSWER-atoms of the same elementwith the same numberof protons but different nuber of
neutrons
Relative Atomic Mass - ANSWER-the average mass of an atom of an element compared to a twelfth of
the mass of an atom of carbon-12.
Relative Isotopic Mass - ANSWER-The mass of an atom of an isotope compared to one-twelfth of the
mass of an atom of carbon-12
Quantum Shell - ANSWER-the energy level of an electron.
Orbital - ANSWER-a region around the nucleus that can hold up to two electrons with opposite spins.
What shape is the S orbital - ANSWER-spherical
What shape is the P orbital - ANSWER-dumbell
First Ionisation Energy - ANSWER-the measure of energy is needed to completely remove one mole of
electron from one mole of gaseous atom
,Second Ionisation Energy - ANSWER-is a measure of energy needed to remove one-mole of electron
from one mole of gaseous ion
Periodicity - ANSWER-A repeating trend in the properties of the elements across the periodic table
Why are copper and chromium important to do with filling up their subshells? - ANSWER-because they
have a half-filled subshell. This gives added stability so minimises electron repulsion
Why is the first ionisation energy the lowest? - ANSWER-it is the lowest because the electron is further
away from the nucleus so less attraction and more shielding by the inner electrons. This means less
energy is needed to remove the electron.
Why does ionisation energy increase as you go across the period? - ANSWER-as you go across the
periodic table there are more protons so more attraction to the electrons so decreasing atomic radii. This
increases the ionisation energy.
first ionisation energy for sodium - ANSWER-see pic
Why does ionisation energy increase from Na to Mg - ANSWER-ionisation energy increases becasue
magnesium has more protons so more attraction to the electron
Why does ionisation energy decrease from Mg to Al - ANSWER-because the electron being removed is
from a new subshell. This means the electron is futher away from the nucleus so less attraction to the
nucleus.
Why does ionisation energy decrease from P to S - ANSWER-There are more electrons in the same
orbital so more repulsion.
What is the trend in ionisation energy as you go down the period? - ANSWER-As you go down periods
the electros get further away from the nucleus and atomic radii increases. This means there is more
shielding by inner electrons.
,Why does successive ionisation energy increase? - ANSWER-because as you remove an electron the ratio
of proton to electron increases. This means more attraction and so more energy needed to remove
electrons.
Explain the stages of mass spectrometer. - ANSWER-Vapourisation- the sample is heated to produce
gaseous atom.
Ionisation- an electron gun is used to knock off electrons from the sample.
Acceleration- the speed is increased to make deflection easier.
Deflection- sample is deflected by electromagnet
Detector- the sample is detected by detector.
Why is fluorine the most reactive element - ANSWER-because it has 7 protons which are pulling the
electron so it is harder to lose electrons
Decribe the trend in reactivity as you go down group 1 - ANSWER-as you go down group one
Delocalised Electrons - ANSWER-electrons that are not associated with any single atom or any single
covalent bond.
Metallic Bonding - ANSWER-the electrostatic forces of attraction between the nuclei of metal cations and
delocalised electrons.
Polar Covalent Bond - ANSWER-type of covalent bond between two atoms where the bonding electrons
are unequally distributed. Because of this, one atoms carries a slight negative charge and the other a
slight positive charge.
Electronegativity - ANSWER-the ability of an atom to attract a bonding pair of electrons
Dipole - ANSWER-said to exist when two charges of equal magnitude but opposite signs are separated by
a small distance.
, Hydrogen Bond - ANSWER-an intermolecular interaction (in which there is some evidence of bond
formation) between a hydrogen atom of a molecule (or molecular fragment) bonded to an atom which is
more electronegative than hydrogen and another atom in the same or a different molecule.
Isoelectronic - ANSWER-contains the same number of electrons
Redox Reaction - ANSWER-a reaction that involves both reduction and oxidation
Oxidation - ANSWER-the loss of electrons
Reduction - ANSWER-the gain of electrons
Oxidising Agent - ANSWER-a species that oxidises another species by removing one or more electrons.
When an oxidising agent reacts it gains electrons and is, therefore, reduced.
Reducing Agent - ANSWER-a species that reduces another species by adding one or more electrons.
When a reducing agent reacts it loses electrons, and is, therefore, oxidised.
Oxidation Number - ANSWER-the charge that an ion has or the charge that it would have if the species
were fully ionic.
Disproportionation - ANSWER-the simultaneous oxidation and reduction of an element in a single
reaction.
Electromotive Force - ANSWER-the standard electrode potential of a half cell (measured under standard
conditions of 298 K, 100 kPa pressure and concentrations of 1 mol dm-3) connected to a standard
hydrogen electrode.
Basic Oxides - ANSWER-are oxides of metals that react with water to form metal hydroxides, and with
acids to form salts and water.
Questions & Answers 2023/2024
how to test for C=C - ANSWER-decolourises bromine water
Atomic Number - ANSWER-number of protons in the nucleus of an atom of that element.
Mass Number - ANSWER-the sum of protons and neutrons in a nuclues of an atom
Isotopes - ANSWER-atoms of the same elementwith the same numberof protons but different nuber of
neutrons
Relative Atomic Mass - ANSWER-the average mass of an atom of an element compared to a twelfth of
the mass of an atom of carbon-12.
Relative Isotopic Mass - ANSWER-The mass of an atom of an isotope compared to one-twelfth of the
mass of an atom of carbon-12
Quantum Shell - ANSWER-the energy level of an electron.
Orbital - ANSWER-a region around the nucleus that can hold up to two electrons with opposite spins.
What shape is the S orbital - ANSWER-spherical
What shape is the P orbital - ANSWER-dumbell
First Ionisation Energy - ANSWER-the measure of energy is needed to completely remove one mole of
electron from one mole of gaseous atom
,Second Ionisation Energy - ANSWER-is a measure of energy needed to remove one-mole of electron
from one mole of gaseous ion
Periodicity - ANSWER-A repeating trend in the properties of the elements across the periodic table
Why are copper and chromium important to do with filling up their subshells? - ANSWER-because they
have a half-filled subshell. This gives added stability so minimises electron repulsion
Why is the first ionisation energy the lowest? - ANSWER-it is the lowest because the electron is further
away from the nucleus so less attraction and more shielding by the inner electrons. This means less
energy is needed to remove the electron.
Why does ionisation energy increase as you go across the period? - ANSWER-as you go across the
periodic table there are more protons so more attraction to the electrons so decreasing atomic radii. This
increases the ionisation energy.
first ionisation energy for sodium - ANSWER-see pic
Why does ionisation energy increase from Na to Mg - ANSWER-ionisation energy increases becasue
magnesium has more protons so more attraction to the electron
Why does ionisation energy decrease from Mg to Al - ANSWER-because the electron being removed is
from a new subshell. This means the electron is futher away from the nucleus so less attraction to the
nucleus.
Why does ionisation energy decrease from P to S - ANSWER-There are more electrons in the same
orbital so more repulsion.
What is the trend in ionisation energy as you go down the period? - ANSWER-As you go down periods
the electros get further away from the nucleus and atomic radii increases. This means there is more
shielding by inner electrons.
,Why does successive ionisation energy increase? - ANSWER-because as you remove an electron the ratio
of proton to electron increases. This means more attraction and so more energy needed to remove
electrons.
Explain the stages of mass spectrometer. - ANSWER-Vapourisation- the sample is heated to produce
gaseous atom.
Ionisation- an electron gun is used to knock off electrons from the sample.
Acceleration- the speed is increased to make deflection easier.
Deflection- sample is deflected by electromagnet
Detector- the sample is detected by detector.
Why is fluorine the most reactive element - ANSWER-because it has 7 protons which are pulling the
electron so it is harder to lose electrons
Decribe the trend in reactivity as you go down group 1 - ANSWER-as you go down group one
Delocalised Electrons - ANSWER-electrons that are not associated with any single atom or any single
covalent bond.
Metallic Bonding - ANSWER-the electrostatic forces of attraction between the nuclei of metal cations and
delocalised electrons.
Polar Covalent Bond - ANSWER-type of covalent bond between two atoms where the bonding electrons
are unequally distributed. Because of this, one atoms carries a slight negative charge and the other a
slight positive charge.
Electronegativity - ANSWER-the ability of an atom to attract a bonding pair of electrons
Dipole - ANSWER-said to exist when two charges of equal magnitude but opposite signs are separated by
a small distance.
, Hydrogen Bond - ANSWER-an intermolecular interaction (in which there is some evidence of bond
formation) between a hydrogen atom of a molecule (or molecular fragment) bonded to an atom which is
more electronegative than hydrogen and another atom in the same or a different molecule.
Isoelectronic - ANSWER-contains the same number of electrons
Redox Reaction - ANSWER-a reaction that involves both reduction and oxidation
Oxidation - ANSWER-the loss of electrons
Reduction - ANSWER-the gain of electrons
Oxidising Agent - ANSWER-a species that oxidises another species by removing one or more electrons.
When an oxidising agent reacts it gains electrons and is, therefore, reduced.
Reducing Agent - ANSWER-a species that reduces another species by adding one or more electrons.
When a reducing agent reacts it loses electrons, and is, therefore, oxidised.
Oxidation Number - ANSWER-the charge that an ion has or the charge that it would have if the species
were fully ionic.
Disproportionation - ANSWER-the simultaneous oxidation and reduction of an element in a single
reaction.
Electromotive Force - ANSWER-the standard electrode potential of a half cell (measured under standard
conditions of 298 K, 100 kPa pressure and concentrations of 1 mol dm-3) connected to a standard
hydrogen electrode.
Basic Oxides - ANSWER-are oxides of metals that react with water to form metal hydroxides, and with
acids to form salts and water.
