St Mary's Catholic High School
Y10 GCSE Chemistry Atoms, isotopes, ions
Q1.An atom of aluminium has the symbol
(a)
Give the number of protons, neutrons and electrons in this atom of aluminium.
Number of protons
..........................................
Number of neutrons
..........................................
Number of electrons
..........................................
(3)
(b)
Why is aluminium positioned in Group 3 of the periodic table?
.............................................................................................................................
............................................................................................................................
(1)
Q2.This question is about atoms and molecules.
(a)
Different atoms have different numbers of sub-atomic particles.
(i)
An oxygen atom can be represented as
O
Explain why the mass number of this atom is 16.
You should refer to the numbers of sub-atomic particles in the nucleus of the atom.
...................................................................................................................
...................................................................................................................
...................................................................................................................
...................................................................................................................
...................................................................................................................
...................................................................................................................
(2)
(ii)
Explain why
C and
C are isotopes of carbon.
You should refer to the numbers of sub-atomic particles in the nucleus of each isotope.
...................................................................................................................
...................................................................................................................
...................................................................................................................
...................................................................................................................
...................................................................................................................
...................................................................................................................
Page 1
(3)
St Mary's Catholic High School
Q3.This question is about atomic structure and elements.
(a)
Complete the sentences.
(i)
The atomic number of an atom is the number of ..................................
(ii)
The mass number of an atom is the number of ....................................
...............................................................................................................
(b)
(1)
(1)
Explain why an atom has no overall charge.
Use the relative electrical charges of sub-atomic particles in your explanation.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(c)
(2)
Explain why fluorine and chlorine are in the same group of the periodic table.
Give the electronic structures of fluorine and chlorine in your explanation.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(2)
(1)
Q4.This question is about atoms and isotopes.
(a)
Atoms contain protons, neutrons and electrons.
A lithium atom has the symbol
Explain, in terms of sub-atomic particles, why the mass number of this lithium atom is 7.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(3)
Page 2
St Mary's Catholic High School
(c)
Two isotopes of oxygen are
and
Describe the similarities and differences between the isotopes
and
You should refer to the numbers of sub-atomic particles in each isotope.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(3)
Q5.
(b)
Iron(III) oxide is a compound which contains iron(III) ions (Fe3+) and oxide ions (O2-).
(i)
Explain in terms of electrons how an iron atom (Fe) can change into an iron(III) ion (Fe3+).
...............................................................................................................
...............................................................................................................
...............................................................................................................
............................................................................................................... (2)
(ii)
The diagram below represents the electronic structure of an oxygen atom (O).
Complete the diagram below to show the electronic structure of an oxide ion (O2-).
(1)
(Total 6 marks)
Page 3
St Mary's Catholic High School
Q6.The Sun produces helium atoms from hydrogen atoms by nuclear fusion reactions.
Hydrogen
(a)
Helium
Describe the differences in the atomic structures of a hydrogen atom and a helium atom.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(b)
(3)
The Sun consists of 73% hydrogen and 25% helium.
The rest is other elements.
One of the other elements in the Sun is neon.
Use the Chemistry Data Sheet to help you to answer these questions.
(i)
Complete the diagram to show the electronic structure of a neon atom.
(1)
(ii)
Why is neon in the same group of the periodic table as helium?
...............................................................................................................
...............................................................................................................
(1)
Page 4
St Mary's Catholic High School
M1.(a)
13 (protons)
1
14 (neutrons)
1
13 (electrons)
1
(b)
has three electrons in outer energy level / shell
allow electronic structure is 2.8.3
1
M2. (a) (i)
nucleus)
(mass number = 16) because there are 8 protons and 8 neutrons (in the
accept mass number is total number of protons and neutrons for 1
mark
2
(ii)
same number of protons or both have 6 protons
accept same atomic number
1
12C has 6 neutrons
1
14C has 8 neutrons
1
accept different number of neutrons for 1 mark
numbers, if given, must be correct
incorrect reference to electrons = max 2 marks
M3.(a)
(i)
protons
allow “protons or electrons”, but do not allow “protons and
electrons”
1
(ii)
protons plus / and neutrons
1
(b)
(because the relative electrical charges are) −(1) for an electron and +(1) for a
proton
allow electrons are negative and protons are positive
1
and the number of electrons is equal to the number of protons
if no other mark awarded, allow 1 mark for the charges cancel out
1
(c)
(the electronic structure of) fluorine is 2,7 and chlorine is 2,8,7
allow diagrams for the first marking point
1
(so fluorine and chlorine are in the same group) because they have the same
number of or 7 electrons in their highest energy level or outer shell
1
Page 5
St Mary's Catholic High School
M4.(a)
because this lithium atom has
3 protons
1
and 4 neutrons
1
mass number is total of neutrons and protons
accept protons and neutrons have a mass of 1
accept number of neutrons = 7 - 3(protons)
ignore mass of electron is negligible
1
(c)
any three from:
max 2 if no numbers given
numbers if given must be correct
•
both have 8 protons
accept same number of protons
18O has 10 neutrons
16O has 8 neutrons
accept different number of neutrons or 18O has two more neutrons
for 1 mark
both have 8 electrons.
accept same number of electrons
•
•
•
3
M5.
(b)
•
(i)
it loses electrons
sharing / covalency = max 1 mark
1
•
three electrons
1
(ii)
8 electrons shown in second shell.
accept dots / crosses / mixture of dots and crosses / e
electrons do not need to be paired
do not allow extra electrons in first shell
1
M6.(a)
hydrogen has one proton whereas helium has two protons
1
hydrogen has one electron whereas helium has two electrons
allow helium has a full outer shell (of electrons)
1
hydrogen has no neutrons or helium has two neutrons
(b)
(i)
2 electrons on first shell and
8 electrons on outer shell
(ii)
1
1
they have a stable arrangement of electrons / they have full outer energy level
/ shell of electrons
1
Page 6