AS-level AQA Physical Chemistry Exam Study
Questions with Complete Solutions
(Verified
Correct Answers) Latest Update 2024
What is carbon dating? - ANSWER The process of using the radioactive isotopes in carbon-14.
All living things contain carbon-14.
Carbon-14 decays slowly in a living organism, and the amount lost is continually replenished as
long as the organism takes in air or food. Once the organism dies, however, it cannot absorb
carbon-14. This means that the amount of the radiocarbon in its tissues steadily decreases.
Because carbon-14 decays at a constant rate, an estimate of the date at which an
organism died can be made by measuring the amount of its residual radiocarbon.
What can carbon dating be used for? - ANSWER To determine the age of carbon-based
meterial up to 60,000 years old. However, it is more accurate for up to 2000 years old.
Describe the nuclear model. - ANSWER Positively charged nucleus in a cloud of negative
electrons.
,Most of the atom is empty space.
Why did Neil's Bohr disagree with the nuclear model? - ANSWER Believed electrons existed in
shells rather than a random cloud .
When electrons moved between shells, a electromagnetic radiation was emitted or absorbed.
What is Bohr's atomic model? - ANSWER Not all electrons in the same shell have equal energy.
Refined nuclear model includes sub shells.
Why is the refined Bohr model used instead of more accurate models that exist today? -
ANSWER As it is simple and explains many experimental observations
Who discovered the neutron and when? - ANSWER James Chadwick in 1932
What did Gilbert Lewis do? - ANSWER He put forward the ideas that:
1) Noble gases were inert due to their full outer shell.
2) Ions were formed when atoms gained or lost electrons
3) Atoms could bond by sharing electrons to form full outer shells
What is meant by the term 'electron cloud probability' - ANSWER You can never really say
where an electron is at any given moment. You can only state the probability that an
electron will be found in a certain area of space.
What did Schrodinger discover? - ANSWER Electrons had some of the properties of waves as
well of those called particles.
,What can Dalton's model of the atom be used for? - ANSWER Working out the geometries of
crystals
What can Bohr's model of the atom be used for? - ANSWER Simple models of covalent and
ionic bonding
Name the 4 subshells. Put them in order of energy from lowest to highest. - ANSWER s, p,
d, and f
How many electrons can each orbital hold? - ANSWER two
How many orbitals are there in each sub-shell? - ANSWER s = one
p = three
d = five
f = seven
How many electrons can each sub-shell hold? - ANSWER s = two
p = six
d = ten
f = fourteen
How many electrons can an s sub shell hold? - ANSWER Two electrons. These electrons both
go in one orbital.
In the example "1s2" what does the "1", "s" and "2" stand for? - ANSWER 1 = Electrons are in
shell one
S = Electrons sit in the s sub-shell
2 = There are two electrons
, What is electron spin? - ANSWER Electrons have two states, 'spin up' and 'spin down'. In
an orbital, each electron will be in a different spin state.
What is the total number of electrons in 4 energy levels? - ANSWER 1st — 1s = 2electrons
2nd — 2s 2p = 8 electrons
3rd — 3s 3p 3d = 16 electrons
4th — 4s 4p 4d 4f = 32 electrons
In what order do electrons fill shells? - ANSWER Lowest energy first.
What happens to the electrons when they fill the p-oribital? Why? - ANSWER They must be
filled singly and then doubly. This is because there is less electron-pair repulsion.
(Think about people on the bus. You don't want to sit next to someone unless you absolutely
have to)
How are ions different from atoms? - ANSWER Ions have different number of protons and
electrons
How are ions formed? - ANSWER When atoms lose or gain electrons
-ive ions formed when electrons are gained
+ive ions formed when electrons are lost
Define the term 'relative atomic mass - ANSWER The average mass of one atom of an element
to one twelfth of the mass of an atom of carbon-12.
Define the term 'relative isotopic mass' - ANSWER The mass of an atom of an isotope
compared with one-twelfth of the mass of an atom of carbon-12.
Questions with Complete Solutions
(Verified
Correct Answers) Latest Update 2024
What is carbon dating? - ANSWER The process of using the radioactive isotopes in carbon-14.
All living things contain carbon-14.
Carbon-14 decays slowly in a living organism, and the amount lost is continually replenished as
long as the organism takes in air or food. Once the organism dies, however, it cannot absorb
carbon-14. This means that the amount of the radiocarbon in its tissues steadily decreases.
Because carbon-14 decays at a constant rate, an estimate of the date at which an
organism died can be made by measuring the amount of its residual radiocarbon.
What can carbon dating be used for? - ANSWER To determine the age of carbon-based
meterial up to 60,000 years old. However, it is more accurate for up to 2000 years old.
Describe the nuclear model. - ANSWER Positively charged nucleus in a cloud of negative
electrons.
,Most of the atom is empty space.
Why did Neil's Bohr disagree with the nuclear model? - ANSWER Believed electrons existed in
shells rather than a random cloud .
When electrons moved between shells, a electromagnetic radiation was emitted or absorbed.
What is Bohr's atomic model? - ANSWER Not all electrons in the same shell have equal energy.
Refined nuclear model includes sub shells.
Why is the refined Bohr model used instead of more accurate models that exist today? -
ANSWER As it is simple and explains many experimental observations
Who discovered the neutron and when? - ANSWER James Chadwick in 1932
What did Gilbert Lewis do? - ANSWER He put forward the ideas that:
1) Noble gases were inert due to their full outer shell.
2) Ions were formed when atoms gained or lost electrons
3) Atoms could bond by sharing electrons to form full outer shells
What is meant by the term 'electron cloud probability' - ANSWER You can never really say
where an electron is at any given moment. You can only state the probability that an
electron will be found in a certain area of space.
What did Schrodinger discover? - ANSWER Electrons had some of the properties of waves as
well of those called particles.
,What can Dalton's model of the atom be used for? - ANSWER Working out the geometries of
crystals
What can Bohr's model of the atom be used for? - ANSWER Simple models of covalent and
ionic bonding
Name the 4 subshells. Put them in order of energy from lowest to highest. - ANSWER s, p,
d, and f
How many electrons can each orbital hold? - ANSWER two
How many orbitals are there in each sub-shell? - ANSWER s = one
p = three
d = five
f = seven
How many electrons can each sub-shell hold? - ANSWER s = two
p = six
d = ten
f = fourteen
How many electrons can an s sub shell hold? - ANSWER Two electrons. These electrons both
go in one orbital.
In the example "1s2" what does the "1", "s" and "2" stand for? - ANSWER 1 = Electrons are in
shell one
S = Electrons sit in the s sub-shell
2 = There are two electrons
, What is electron spin? - ANSWER Electrons have two states, 'spin up' and 'spin down'. In
an orbital, each electron will be in a different spin state.
What is the total number of electrons in 4 energy levels? - ANSWER 1st — 1s = 2electrons
2nd — 2s 2p = 8 electrons
3rd — 3s 3p 3d = 16 electrons
4th — 4s 4p 4d 4f = 32 electrons
In what order do electrons fill shells? - ANSWER Lowest energy first.
What happens to the electrons when they fill the p-oribital? Why? - ANSWER They must be
filled singly and then doubly. This is because there is less electron-pair repulsion.
(Think about people on the bus. You don't want to sit next to someone unless you absolutely
have to)
How are ions different from atoms? - ANSWER Ions have different number of protons and
electrons
How are ions formed? - ANSWER When atoms lose or gain electrons
-ive ions formed when electrons are gained
+ive ions formed when electrons are lost
Define the term 'relative atomic mass - ANSWER The average mass of one atom of an element
to one twelfth of the mass of an atom of carbon-12.
Define the term 'relative isotopic mass' - ANSWER The mass of an atom of an isotope
compared with one-twelfth of the mass of an atom of carbon-12.
