Q1.
An atom of calcium,
(i)
, is ionised by removing two electrons.
State the number of protons, neutrons and electrons in the ion formed.
protons............................................
neutrons...........................................
electrons..........................................
(3)
(ii)
Calculate the charge of the ion.
charge ........................................... C
(1)
(iii)
Calculate the specific charge of the ion.
specific charge ................................... C kg−1
(2)
(Total 6 marks)
Q2.
(a) The nucleus of a particular atom has a nucleon number of 14 and a proton number of
6.
(i)
State what is meant by nucleon number and proton number.
nucleon number ....................................................................................
...............................................................................................................
...............................................................................................................
proton number ......................................................................................
...............................................................................................................
...............................................................................................................
(1)
(ii)
Calculate the number of neutrons in the nucleus of this atom.
answer = .....................................
(1)
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(iii)
Calculate the specific charge of the nucleus.
answer = .......................... Ckg–1
(3)
(b)
The specific charge of the nucleus of another isotope of the element is 4.8 × 107 Ckg–1.
(i)
State what is meant by an isotope.
...............................................................................................................
...............................................................................................................
...............................................................................................................
(2)
(ii)
Calculate the number of neutrons in this isotope.
answer = .....................................
(3)
(Total 10 marks)
Q3.
(a) State what is meant by the specific charge of a nucleus and give an appropriate unit
for this quantity.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
unit: ...................................................
(2)
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(b)
Nucleus X has the same nucleon number as nucleus Y. The specific charge of X is 1.25
times greater than that of Y.
(i)
Explain, in terms of protons and neutrons, why the specific charge of X is greater
than that of Y.
...............................................................................................................
...............................................................................................................
...............................................................................................................
...............................................................................................................
(2)
(ii)
Nucleus X is
nucleus Y.
. Deduce the number of protons and the number of neutrons in
number of protons ...........................
number of neutrons ..........................
(4)
(Total 8 marks)
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M1.
(a)
(i)
protons = 20
neutrons = 28
electrons = 18
3
(ii)
2 × 1.6 × 10−19 = 3.2 × 10−19
-ve sign loses mark
(C)
1
specific charge = 3.2 × 10−19 / (48 ×; 1.67 × 10−27 +18 × 9.11 × 10−31)
(iii)
specific charge = 4.0 × 106 C kg−1
Allow 1.66
Allow CE from (ii)
First mark is for mass if miss out electron mass and do not justify
lose first mark
2
[6]
M2.
(a)
(i) nucleon number is the number of protons and neutrons OR mass number
proton number is the number of protons OR atomic number
1
(ii)
14 – 6 = 8
1
(iii)
specific charge = 6 × 1.6 × 10–19 /(14 × 1.66 × 10–27
)
specific charge = 4.1 × 107 (C kg–1)
3
(b)
(i)
isotopes are variations of an element that have same
proton/atomic number
but different nucleon number OR different number of neutrons
2
(ii)
4.8 × 107 = 6 × 1.6 × 10–19
/(A × 1.66 × 10–27)
A = 6 × 1.6 × 10–19/(4.8 × 107 × 1.66 × 10–27)
A = 12
Number of neutrons = 12-6
3
[10]
M3.
(a)
the ratio of charge to mass of nucleus
C kg−1
2
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(b)
(i)
number of protons and neutrons the same or number of neutrons less or
mass the same
but more protons therefore greater charge
2
(ii)
answers add up to 10
number of protons = 4
number of neutrons = 10 − 4 = 6
evidence of correct calculation
eg 5q = 1.25 × ?q
?=4
4
[8]
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