Questions
Q1.
Each element has an atomic number.
(i) State what is meant by atomic number.
(1)
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(ii) The atomic number of boron is 5.
Boron exists as two isotopes boron-10 and boron-11.
Use this information to explain why boron-10 and boron-11 are isotopes.
(2)
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Q2.
The positions of five elements, A, B, C, D and E, are shown in the periodic table.
These letters are not the atomic symbols of these elements.
(a) Use only elements A, B, C, D and E to answer (i) and (ii).
(i) Give the letters of all the elements that are metallic.
(1)
(ii) Give the letters of the two elements that have the most similar chemical properties.
(1)
(b) An atom of element B contains more protons than an atom of element A.
State how many more protons there are in an atom of element B than in an atom of element A.
(1)
(c) An atom of element E has atomic number 10 and mass number 22.
(i) How many electrons does this atom contain?
Put a cross (
) in the box next to your answer.
(1)
A 10
B 12
C 22
D 32
(ii) 10% of the atoms in a sample of element E have a mass number of 22.
All the other atoms in this sample have a mass number of 20.
Calculate the relative atomic mass of element E.
(3)
relative atomic mass = . . . . . . . . . . . . . . . . . . . . . .
(d) The element below E in the periodic table is used to fill filament light bulbs.
Explain why this element is suitable for this use.
(2)
(Total for Question is 9 marks)
Q3.
Boron exists as two isotopes.
These are boron-10, 105B, and boron-11, 115B.
(a) The diagram shows an atom of the isotope, boron-10.
(i) State the electronic configuration of boron.
(1)
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(ii) Complete the sentence by putting a cross (
) in the box next to your answer.
In the periodic table, boron is in period
(1)
A 2
B 3
C 5
D 10
(iii) The table shows the three particles present in atoms and their relative masses and charges.
Complete the table.
(2)
particle
relative mass
relative charge
electron
neutron
proton
+1
*(b) A sample of boron contains 20% boron-10 and 80% boron-11.
In part (a) you were given the structure of a boron-10 atom.
Describe the structure of a boron-11 atom and explain why, in this sample, boron has a relative atomic
mass of 10.8.
(6)
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(c) Mendeleev was a Russian chemist who produced the first version of the periodic table.
Give one similarity and one difference between his version of the periodic table and the periodic
table shown on page 2.
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(2)
(Total for Question is 12 marks)
Q4.
Boron exists as two isotopes.
These are boron-10, 105B, and boron-11, 115B.
* A sample of boron contains 20% boron-10 and 80% boron-11.
In part (a) you were given the structure of a boron-10 atom.
Describe the structure of a boron-11 atom and explain why, in this sample, boron has a relative atomic
mass of 10.8.
(6)
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Mark Scheme
Q1.
Answer
(i)
number of protons
(in nucleus of atom)
(ii)
An explanation
including
 (atoms of) both
contain 5 /same
number of
protons/same
atomic number (1)
 boron-10 atoms
contain 5 neutrons
but boron-11 atoms
contain 6 neutrons /
different numbers of
neutrons/ different
mass number (1)
Acceptable
answers
ignore number of
electrons
eg number of
protons and
electrons worth (1)
ignore
electrons boron-11
atoms contain 1
more neutron /
boron-10 atoms
contain 1 less
neutron
Mark
(1)
(2)
Q2.
Answer
(a)(i)
A, B and C
(a)(ii)
A and B
(b)
(c)(i)
(c)(ii)
8 (protons)
A : 10
(in 100
atoms)
mass
of mass number 20
atoms = 20 × 90 (1)
mass of mass
number 22 atoms =
22 × 10 (1)
relative
atomic mass = (22 ×
10) + (20 ×90)/100
(=20.2) (1)
OR
20
contributes = 90/100
×20(1)
22 contributes
= 10/100 ×22(1)
relative atomic
mass 90/100 × 20 +
10/100 x 22 (= 20.2)
(1)
An explanation
linking any two of
(the element is)
group 0 / noble gas
/unreactive / inert /
does not react (1)
(has) 8 electrons
/ full outer shell (1)
prevents filament
from reacting (1)
(d)
Acceptable
answers
Mg Ca Au (any
order) magnesium
calcium gold (any
order)
Mg Ca (any order)
magnesium calcium
(any order)
20.2 = 3 marks
21.8 = 2 marks (only
1 error made)
ignore 'not very
reactive' does not
gain / lose / share
electrons
Mark
(1)
(1)
(1)
(1)
(3)
(2)
Q3.
Answer
(a)(i)
(a)(ii)
(a)(iii)
Acceptable
answers
Mark
(1)
(1)
(2)
2.3
A
4 correct = 2 marks
2/3 correct = 1 mark
1/0 correct = 0 mark
QWC
*(b)
Indicative Content
Mark
An explanation
linking some of the
following Structure
of boron-11
boron-11 atom has
 5 /same number
of protons
 5 /same number
of electrons
 6 neutrons / one
more neutron than
boron 10 Working
out RAM
relative atomic mass
is 10.8 because
 weighted mean
 more boron-11
than boron-10
 boron-11 atoms
are heavier
 (therefore)
relative atomic mass
nearer 11 than 10
OR
 in sample given
20/100 of the atoms
have a mass of 10
 in sample given
80/100 of the atoms
have a mass of 11
 20/100*10=2
 80/100*11=8.8
 2+8.8=10.8 NB
the diagram in part
(a) gives the
structure for boron10 so do not give
credit for this (even if
claimed to be
structure of boron-11
(6)
Level
1
0
1-2
by referring to it as
'it')
No rewardable content
 a limited description e.g. boron-11 has
5 protons and 6 neutrons
 the answer communicates ideas using
simple language and uses limited scientific
terminology
 spelling, puncuation and grammar are
used with limited accuracy
2
3-4
 a simple explanation e.g. boron-11 has
5 protons, 5 electrons and 6 neutrons and is
heavier than boron-10.
 the answer communicates ideas
showing some evidence of clarity and
organisation and uses scientific terminology
appropriately
 spelling, punctuation and grammar are
used with some accuracy
3
5-6
 a detailed explanation e.g. boron-11
has 5 protons, 5 electrons and 6 neutrons, is
heavier than boron-10 and there is more of
boron-11 therefore relative atomic mass
nearer to 11 than 10.
 the answer communicates ideas clearly
and coherently uses a range of scientific
terminology accurately
 spelling, puncuation and grammar are
used with few errors
Answer
(c)
Answer should
include one idea
from each list
similarities
both put
 elements into
groups / periods (1)
 elements with
similar properties in
same group (1)
 metals and nonmetals in separately
(1) differences
Mendeleev's table
 was arranged
by relative atomic
mass(1)
 had gaps (1)
 had fewer
elements (1)
 did not include
the noble gases (1)
Acceptable
answers
Mark
(2)
reverse argument for
modern periodic
table specific
examples e.g
germanium
Q4.
Indicative Content
QWC
Level
1
*
0
1-2
Mark
(6)
An explanation
linking some of the
following Structure
of boron-11
boron-11 atom has
 5 /same number
of protons
 5 /same number
of electrons
 6 neutrons / one
more neutron than
boron 10 Working
out RAM
relative atomic mass
is 10.8 because
 weighted mean
 more boron-11
than boron-10
 boron-11 atoms
are heavier
 (therefore)
relative atomic mass
nearer 11 than 10
OR
 in sample given
20/100 of the atoms
have a mass of 10
 in sample given
80/100 of the atoms
have a mass of 11
 20/100*10=2
 80/100*11=8.8
 2+8.8=10.8 NB
the diagram in part
(a) gives the
structure for boron10 so do not give
credit for this (even if
claimed to be
structure of boron-11
by referring to it as
'it')
No rewardable content
 a limited description e.g. boron-11 has
5 protons and 6 neutrons
 the answer communicates ideas using
simple language and uses limited scientific
terminology
 spelling, puncuation and grammar are
used with limited accuracy
2
3-4
 a simple explanation e.g. boron-11 has
5 protons, 5 electrons and 6 neutrons and is
heavier than boron-10.
 the answer communicates ideas
showing some evidence of clarity and
organisation and uses scientific terminology
appropriately
 spelling, punctuation and grammar are
used with some accuracy
3
5-6
 a detailed explanation e.g. boron-11
has 5 protons, 5 electrons and 6 neutrons, is
heavier than boron-10 and there is more of
boron-11 therefore relative atomic mass
nearer to 11 than 10.
 the answer communicates ideas clearly
and coherently uses a range of scientific
terminology accurately
 spelling, puncuation and grammar are
used with few errors