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Question 1
A subatomic particle has relative charge , negligible relative mass and occupies the space outside the nucleus. What is the particle?
A.
Electron
B.
Proton
C.
Nucleon
D.
Neutron
Question 2
In Rutherford's gold foil experiment, most alpha particles passed through the foil without deflection. What does this observation support?
A.
Atoms are mostly empty space.
B.
Electrons are located in the nucleus.
C.
Protons are spread throughout the atom.
D.
The nucleus has a negative charge.
Question 3
The nuclear symbol for an ion is . What are the numbers of protons, neutrons and electrons in this ion?
A.
26 protons, 30 neutrons, 29 electrons
B.
30 protons, 26 neutrons, 23 electrons
C.
56 protons, 26 neutrons, 53 electrons
D.
26 protons, 30 neutrons, 23 electrons
Question 4
An atom has a diameter of approximately and its nucleus has a diameter of approximately . The diameter of the atom is how many times greater than the diameter of the nucleus?
A.
B.
C.
D.
Question 5
Which pair is best described as isotopes of the same element?
A.
and
B.
and
C.
and
D.
and
Question 6
A mass spectrum of an element plots relative abundance on the vertical axis. What is plotted on the horizontal axis?
A.
Mass-to-charge ratio,
B.
Percentage abundance,
C.
Atomic number,
D.
Neutron number,
Question 7
A selenium ion contains 34 protons, 45 neutrons and 36 electrons.
Determine the mass number of this ion.
[1]
Write the nuclear symbol for this ion.
[2]
State which subatomic particle determines the identity of the element.
[1]
0
Question 8
An element has two naturally occurring isotopes with mass numbers 63 and 65. Their percentage abundances are and , respectively. What is the relative atomic mass of the element, using these mass numbers?
A.
64.0
B.
64.4
C.
63.6
D.
65.0
Question 9
The mass spectrum of an element shows two singly charged isotope peaks at and with relative abundances and , respectively. What is the relative atomic mass of the element?
A.
71.00
B.
70.00
C.
70.20
D.
69.80
Question 10
A doubly charged isotope ion produces a peak at in a mass spectrum. What is the relative mass of the ion?
A.
16
B.
32
C.
34
D.
64
Question 11
The mass spectrum of an element has two singly charged isotope peaks at and . The relative intensities are in the ratio , respectively. What conclusion follows from the spectrum?
A.
The isotope with mass 37 is about three times more abundant than the isotope with mass 35.
B.
The element has a relative atomic mass of exactly 36.0.
C.
The isotope with mass 35 is about three times more abundant than the isotope with mass 37.
D.
The two isotopes have equal natural abundance.
Question 12
In an alpha-particle scattering experiment, alpha particles were directed at a thin metal foil. Most alpha particles passed straight through the foil, but a very small proportion were deflected through angles greater than .
Explain what is implied by most alpha particles passing straight through the foil.
[1]
Explain what is implied by a very small proportion of alpha particles being deflected through angles greater than .
[2]
0
Question 13
A particular atom has a diameter of . Its nucleus has a diameter of .
Calculate the ratio of the diameter of the atom to the diameter of the nucleus.
[1]
Explain why a diagram showing a visible nucleus inside an atom is not to scale.
[1]
State where most of the mass of an atom is found.
[1]
0
Question 14
Two neutral atoms of copper are represented by and .
State why these atoms are isotopes of copper.
[1]
Determine the number of neutrons in each atom.
[1]
Explain why these isotopes have very similar chemical properties but may have slightly different physical properties.
[2]
0
Question 15
Naturally occurring element Y contains two isotopes. The isotope with mass number 10 has an abundance of and the isotope with mass number 11 has an abundance of .
Calculate the relative atomic mass, , of element Y using these data.
[2]
Explain why the relative atomic mass is not a whole number.
[1]
0
Question 16
The mass spectrum of a sample of magnesium is shown. Assume all ions shown have a charge number of .
State why the values correspond to the mass numbers of the magnesium isotopes.
[1]
The peaks occur at values 24, 25 and 26 with relative abundances , and , respectively. Calculate the relative atomic mass of magnesium.
[2]
Identify the most abundant isotope in the sample.
[1]
0
Question 17
The mass spectrum of bromine contains two main peaks. Assume the ions are singly charged.
State what is represented by the height or area of each peak in an elemental mass spectrum.
[1]
The two peaks are at and , with relative abundances and , respectively. Calculate the relative atomic mass of bromine.
[2]
Explain what the two similar peak heights indicate about naturally occurring bromine.
[1]
0
Question 18
A simulation of Rutherford's alpha-particle scattering experiment was carried out using a very thin metal foil. The outcomes for a large number of alpha particles are shown.
| Outcome | Number of alpha particles | Percentage / % |
|---|---|---|
| Pass straight through | 9700 | 97.0 |
| Small-angle deflection | 250 | 2.5 |
| Large-angle deflection | 40 | 0.4 |
| Backward scattering | 10 | 0.1 |
| Total | 10000 | 100.0 |
State the most common outcome for the alpha particles.
[1]
Explain how the data support the nuclear model of the atom.
[2]
Suggest why increasing the foil thickness would increase the number of deflected alpha particles.
[1]
0
Question 19
The table shows nuclear symbols for some atoms and ions.
| Item | Given data |
|---|---|
| 1 | ⁶⁵₂₉Cu²⁺ |
| 2 | 17 protons, 20 neutrons, 18 electrons |
Deduce the number of protons, neutrons and electrons in .
[2]
Deduce the nuclear symbol for the species with 17 protons, 20 neutrons and 18 electrons.
[2]
0
Question 20
A student prepared a scale drawing of an atom and its nucleus. The table compares the real diameters with the diameters used in the drawing.
| Object | Real diameter / m | Diameter in drawing / mm |
|---|---|---|
| Atom | 2.0 × 10^-10 | 100 |
| Nucleus | 2.0 × 10^-15 | 1 |
Convert the atomic diameter of into picometres.
[1]
Calculate the ratio of the atomic diameter to the nuclear diameter, using for the nuclear diameter.
[1]
Explain why the student's drawing is not to scale and what this implies about atomic structure.
[2]
0
Question 21
A mass spectrum has peaks at and with relative intensities 10.0 and 9.0, respectively. The ions are singly charged. What is the relative atomic mass calculated from these data?
A.
203.00
B.
203.95
C.
204.00
D.
204.90
Question 22
A student calculates a relative atomic mass from a printed mass spectrum and obtains a value slightly different from the data booklet value. The calculation method is correct. What is the most likely explanation?
A.
The operational details of the mass spectrometer must be included in the calculation.
B.
Peak heights were estimated from the graph or rounded isotope masses were used.
C.
Mass spectra cannot be used to determine relative atomic masses.
D.
The vertical axis gives atomic number rather than abundance.
Question 23
Element Q has two naturally occurring isotopes with mass numbers 69 and 71. Its relative atomic mass is 69.72.
Let be the percentage abundance of the isotope with mass number 69. Write an expression for the relative atomic mass in terms of .
[1]
Calculate the percentage abundance of each isotope.
[2]
State which isotope is more abundant and justify your answer.
[1]
0
Question 24
A mass spectrum of an unknown element contains two isotope peaks. The data booklet gives values of 35.45 for chlorine, 39.95 for argon and 32.06 for sulfur.
The peaks are at and with relative abundances and , respectively. Calculate the relative atomic mass of the unknown element.
[2]
Identify the unknown element using the data booklet values given.
[1]
Explain why the relative atomic mass is closer to 35 than to 37.
[1]
0
Question 25
A mass spectrum of silicon gives three peaks with intensities in arbitrary units rather than percentages. The peaks at , 29 and 30 have intensities 100.0, 5.1 and 3.4, respectively. Assume all ions are singly charged.
Explain why the intensities must be normalised before calculating the relative atomic mass.
[1]
Calculate the relative atomic mass of silicon from these data.
[3]
0
Question 26
The mass spectrum of a compound containing carbon and hydrogen has a molecular ion peak at and fragment ion peaks at and . Assume the ions are singly charged.
Define the term fragment ion.
[1]
Suggest the formula of the fragment ion at .
[1]
Explain how fragment ion peaks can help determine the structure of a compound.
[2]
0
Question 27
A naturally occurring sample of element M contains four isotopes. The relative isotopic masses and percentage abundances are shown.
| Relative isotopic mass | Percentage abundance / % |
|---|---|
| 84 | 0.56 |
| 86 | 9.86 |
| 87 | 7.00 |
| 88 | 82.58 |
Calculate the relative atomic mass, , of element M using the data.
[3]
Explain why the value of is closest to 88.
[1]
Suggest why the calculated value may differ slightly from a value in a data booklet.
[1]
0
Question 28
An isotope tracer experiment was used to follow the oxygen atom in the reaction shown. The oxygen atom in was labelled with the isotope .
Identify the product that contains most of the label.
[1]
Suggest what the tracer result shows about the fate of the oxygen atom originally in .
[1]
Explain why an oxygen isotope can be used as a tracer in this experiment.
[2]
0
Question 29
The graph shows the relative rate of diffusion of gaseous molecules containing different isotopes of the same element under the same conditions.
Describe the relationship shown in the graph.
[1]
Calculate the percentage decrease in relative rate from the lightest to the heaviest isotopic molecule.
[1]
Explain why isotopic molecules can have different physical properties but very similar chemical properties.
[2]
0
Question 30
The mass spectrum of a naturally occurring sample of element X is shown. The ions are singly charged.
State what each peak in the spectrum represents.
[1]
Calculate the relative atomic mass of X from peaks at and with relative abundances of and , respectively.
[2]
Explain why the peak positions can be treated as isotope mass numbers in this calculation.
[1]
0
Question 31
The mass spectrum of a naturally occurring element is shown along with a small extract from a data table of relative atomic masses.
| Source | m/z | Relative abundance / % | Element | Relative atomic mass |
|---|---|---|---|---|
| Mass spectrum | 28 | 92.2 | — | — |
| Mass spectrum | 29 | 4.7 | — | — |
| Mass spectrum | 30 | 3.1 | — | — |
| Data table extract | — | — | Aluminium | 26.98 |
| Data table extract | — | — | Silicon | 28.09 |
| Data table extract | — | — | Phosphorus | 30.97 |
Calculate the relative atomic mass from peaks at , 29 and 30 with percentage abundances , and , respectively.
[2]
Identify the element if the data table lists aluminium, silicon and phosphorus with approximate values 26.98, 28.09 and 30.97.
[1]
Explain why there are three peaks in the elemental mass spectrum.
[1]
0
Question 32
A geological sample contains an element with two isotopes. Its mass spectrum shows two singly charged isotope peaks with an intensity ratio of for the lower and higher peaks, respectively.
The lower and higher peaks occur at and , respectively. Determine the percentage abundance of each isotope.
[1]
Calculate the relative atomic mass of the element in this sample.
[2]
Suggest one reason why this value may differ slightly from a data booklet value for the same element.
[1]
0
Question 33
A mass spectrum of element Y gives peak intensities that are not percentages. The ions are singly charged.
Convert the relative intensity of the peak at to a percentage abundance.
[1]
Calculate the relative atomic mass of Y using peaks at , 25 and 26 with relative intensities 315, 40 and 45.
[3]
State why the most intense peak does not by itself give the relative atomic mass.
[1]
0
Question 34
Mass spectra were recorded for chlorine from two different samples. The spectra show the same two isotope peaks but different relative abundances.
Calculate for sample A, which contains and .
[2]
Calculate for sample B, which contains and .
[2]
Compare the isotope composition of the two samples using the spectra.
[1]
0
Question 35
A computer simulation represents the scattering of alpha particles by a thin metal foil. The diameter of a typical atom is taken as and the diameter of its nucleus as .
The simulation is based on Rutherford's gold foil experiment.
I.
Explain how one observation supports the conclusion that atoms are mostly empty space.
[1]
II.
Explain how the observations support the existence of a small, dense, positively charged nucleus.
[2]
Consider the scale of the atom and the nucleus.
I.
Determine the ratio of the diameter of the atom to the diameter of the nucleus.
[1]
II.
Calculate the diameter of an atom on a model in which the nucleus has a diameter of .
[2]
Explain why the mass number of an atom is determined by the nucleus rather than by the electrons.
[1]
0
Question 36
Strontium bromide is used in some specialist materials. One ion in a sample is represented by the nuclear symbol . A bromide ion in the same sample contains 44 neutrons.
Use the nuclear symbols and charges of the ions.
I.
Deduce the number of protons, neutrons and electrons in .
[2]
II.
Write the full nuclear symbol, including charge, for the bromide ion.
[1]
Compare the roles of protons, neutrons and electrons in determining the identity and charge of these particles.
[2]
Explain why and have very similar chemical properties.
[1]
0
Question 37
Silicon atoms are used to make very small electronic devices. A typical silicon atom has a radius of and its nucleus has a radius of about .
Compare the size of the atom and its nucleus.
I.
Convert both radii to metres and determine how many times larger the radius of the atom is than the radius of the nucleus.
[3]
II.
On a model, the atom is drawn with a radius of . Calculate the radius of the nucleus on the same scale.
[1]
Explain why the nucleus contains almost all the mass of a silicon atom but occupies only a tiny fraction of the atom's volume.
[2]
0
Question 38
A spectrum of element Z was recorded using ions with charge number . The table gives the observed values and relative abundances.
| m/z | Relative abundance / % |
|---|---|
| 32.0 | 69.1 |
| 33.0 | 30.9 |
Deduce the mass numbers of the two isotopes if the observed peaks are at and .
[1]
Calculate the relative atomic mass of Z if the relative abundances of the two peaks are and , respectively.
[2]
Suggest the error in calculating directly from the observed values.
[1]
0
Question 39
A low-resolution mass spectrum of an element has two broad isotope peaks. A student estimated the isotope abundances from peak heights, but the analyst reported that peak areas should be used.
| Isotope mass / u | Peak height / a.u. | Integrated area / a.u. |
|---|---|---|
| 10 | 40 | 40 |
| 11 | 30 | 60 |
Calculate using the peak areas for isotopes with masses 10 and 11. The integrated areas are 40 and 60, respectively.
[2]
The student used peak heights of 40 and 30 for the same two isotopes. Calculate the value of the student would obtain.
[1]
Evaluate the student's method for this spectrum.
[2]
0
Question 40
A purified sample of an element, X, contains three naturally occurring isotopes. Their mass numbers and percentage abundances are shown in the table.
| Mass number | Percentage abundance / % |
|---|---|
| 50 | 4.35 |
| 52 | 83.79 |
| 53 | 11.86 |
Consider the meaning of isotope notation.
I.
Define the term isotope.
[1]
II.
Explain why all isotopes of X occupy the same position in the periodic table.
[1]
Calculate the relative atomic mass, , of X using the data in the table.
[3]
Another sample contains only and and has . Calculate the percentage abundance of in this sample.
[2]
Suggest why a sample enriched in could have a slightly different density from a natural sample of X.
[1]
0
Question 41
A tracer experiment investigates the source of the oxygen gas produced during a reaction involving water and carbon dioxide in green plant cells. In one experiment the water contains atoms; in another the carbon dioxide contains atoms. The isotope composition of the oxygen gas is then analysed.
Consider the isotope .
I.
State how differs from .
[1]
II.
Deduce the numbers of protons, neutrons and electrons in a neutral atom.
[2]
Explain why -labelled water can be used as a tracer in this experiment.
[2]
Evaluate the conclusion that the oxygen atoms in the oxygen gas product come from water rather than carbon dioxide.
[2]
0
Question 42
A sample of chlorine from an industrial process contains only and . The relative atomic mass of chlorine in this sample is 35.62.
Use the isotope composition of the chlorine sample.
I.
Calculate the percentage abundance of each chlorine isotope in this sample.
[2]
II.
Calculate the average relative molecular mass of molecules in this sample.
[1]
Explain why the relative atomic mass of chlorine is not a whole number and why a value calculated using mass numbers may differ slightly from a data booklet value.
[2]
Discuss whether and have identical chemical and physical properties.
[3]
0
Question 43
The mass spectrum of a naturally occurring sample of an element has two main peaks. The peak heights have been calibrated so that they are proportional to isotope abundance.
Interpret the mass spectrum.
I.
Explain what the value of an ion represents and why the peak positions can be used to identify isotopes in this spectrum.
[2]
II.
Calculate the relative atomic mass of the element using peaks at and with relative abundances of and , respectively.
[2]
Identify the element using the calculated relative atomic mass and the isotope pattern.
[1]
Discuss three limitations or assumptions involved in using this mass spectrum to determine a data booklet value of .
[3]
0
Question 44
Two mineral samples contain boron. Their mass spectra each show peaks due to and . The relative intensities for sample A are 23 and 100, respectively.
Use the spectrum for sample A.
I.
Convert the relative intensities for sample A into percentage abundances.
[2]
II.
Calculate the relative atomic mass of boron in sample A.
[2]
Compare the spectra of samples A and B and evaluate whether the samples have the same isotopic composition.
[2]
Explain why the two boron samples can have different mass spectra but very similar chemical reactions.
[1]
0
Question 45
The mass spectrum of a compound containing carbon, hydrogen and bromine has two molecular ion peaks of approximately equal height at and . Other important peaks occur as a pair near the bromine isotope masses and as a peak at .
Interpret the molecular ion region of the spectrum.
I.
Explain why two molecular ion peaks separated by two units and of approximately equal height suggest the presence of one bromine atom.
[2]
II.
Deduce the formula of the lower-mass molecular ion if it contains , three atoms and .
[1]
Calculate the average relative molecular mass of using , and .
[2]
Discuss how the fragment ion peaks support the proposed composition of the compound.
[2]
0
Question 46
A copper sample gives two singly charged isotope peaks in a mass spectrum. The relative intensities of the peaks due to and are 100 and 45, respectively. The precise isotopic masses are 62.93 and 64.93.
Use the two isotope peaks for the copper sample.
I.
Convert the relative intensities into percentage abundances.
[2]
II.
Calculate the relative atomic mass of copper in this sample using the precise isotopic masses.
[2]
Explain why the calculated is not exactly equal to the value of either peak.
[1]
second copper sample has a higher calculated than this sample. Suggest one change in isotopic composition that could explain this.
[1]
0
Question 47
The mass spectrum of a neon sample contains peaks from singly charged and doubly charged ions. The singly charged isotope peaks occur at , and , with relative abundances of , and , respectively.
Consider the peaks due to doubly charged ions.
I.
Deduce the charge number, , of an ion from that gives a peak at .
[1]
II.
Explain why the peak at should not be interpreted as evidence for a neon isotope with mass number 10.
[2]
Calculate the relative atomic mass of neon from the singly charged isotope peaks.
[3]
Evaluate the effect on the calculated if the smaller doubly charged peaks were incorrectly treated as additional singly charged isotope peaks.
[2]
0
Question 48
A mineral sample is converted into gaseous atoms and analysed by mass spectrometry. The main singly charged peaks occur at , and with relative intensities , and , respectively.
Use the three main peaks in the mass spectrum.
I.
Calculate the relative atomic mass of the element represented by these peaks.
[3]
II.
Identify the element using the isotope pattern and calculated .
[1]
Explain why the atomic number of the element cannot be read directly from this mass spectrum.
[2]
very small additional peak is observed at . Evaluate whether it should be included in the calculation of the relative atomic mass for the element.
[2]
0
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