Unit 1 – Atomic Structure
Unit 1 - Jan 2009
Q1.
 (a)  A gaseous sample of an element can be analysed using a mass spectrometer.
(i)   Describe briefly how positive ions are formed from gaseous atoms in a mass spectrometer.
(2)
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(ii)   What is used to accelerate the positive ions in a mass spectrometer?
(1)
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(iii)   What is used to deflect the positive ions in a mass spectrometer?
(1)
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(b)  The following data were obtained from the mass spectrum of a sample of chromium.

Calculate the relative atomic mass of chromium in this sample.  Give your answer to three significant figures.
(2)

(c)  Explain why the four isotopes of chromium behave identically in chemical reactions.
(1)
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(d)  In which block of the Periodic Table is chromium found?
(1)
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(Total for question = 8 marks)

Unit 1 - Jun 2009
Q2.
 The mass spectrum for a sample of a metal is shown below.

The relative atomic mass of the metal is
   A     63.2
   B     63.4
   C     63.6
   D     64.0
(Total for question = 1 mark)

Q3.
Which of the following ions would undergo the greatest deflection in a
 mass spectrometer?
   A     35Cl2+
   B     35Cl+
   C     37Cl+
   D     35Cl37Cl+
(Total for question = 1 mark)

Q4.
The nucleus of a  atom contains
   A     11 protons and 12 neutrons.
   B     11 protons and 12 electrons.
   C     23 protons and 11 neutrons.
   D     23 protons and 11 electrons.
(Total for question = 1 mark)

Unit 1 - Jan 2010
Q5.

(Total for question = 1 mark)
Q6.
Chlorine has two isotopes with relative isotopic mass 35 and 37. Four m/z values are
 given below. Which will occur in a mass spectrum of chlorine gas, Cl2, from an ion
 with a single positive charge?
   A      35.5
   B      36
   C      71
   D      72
(Total for question = 1 mark)

Unit 1 - Jun 2010
Q7.
The diagram below shows a mass spectrometer, which can be used to determine the percentage abundances of isotopes in an element.

(a) Explain, in terms of sub-atomic particles, what is meant by the term isotopes.
(2)
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(b) Describe the role of the following parts of the mass spectrometer.
(i) Electric field
(1)
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(ii) Magnetic field
(1)
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(c) A sample of the element barium is made up of four isotopes. The data below were taken from a mass spectrum of this sample.

Calculate the relative atomic mass of the sample, giving your answer to one decimal place.
(2)

(d) The element bromine has two stable isotopes, 79Br and 81Br. How many peaks corresponding to Br2+ ions would be seen in the mass spectrum of bromine? Justify your answer.
(2)
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 (e) Suggest another application of mass spectrometry, other than to determine the
       relative atomic mass of an element.
(1)
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 (Total for question = 9 marks)
Unit 1 - Jan 2011
Q8.
 The relative atomic mass of an element is determined using a mass spectrometer.
(a) Define the term relative atomic mass.
(2)
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(b) The mass spectrum of rubidium is shown below.

(i) The mass spectrum of rubidium is shown below.
(1)
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(ii) Use the spectrum to calculate the relative atomic mass of rubidium.
(2)

(Total for question = 5 marks)

Unit 1 - Jan 2012
Q9.
(a) State how the following processes are achieved in a mass spectrometer.
     (i) Ionization of the sample.
(1)
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     (ii) Acceleration of the ions.
(1)
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     (iii) Deflection of the ions.
(1)
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(b) State how you could find the molecular mass of a substance from its mass spectrum.
(1)
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(c) Living things take up the radioactive isotope carbon-14 from the atmosphere. In recent years a particular linen cloth was shown, using mass spectrometry, to have been made from flax grown in the early 14th century. Suggest how mass spectrometry can be used to estimate the age of the cloth.
(2)
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(Total for question = 6 marks)

Unit 1 - Jun 2012
Q10.
 (a)  Define the term relative isotopic mass.
(2)
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(b) Naturally occurring chlorine contains 75.53% of 35Cl and 24.47% of 37Cl.
(i) Calculate the relative atomic mass of chlorine to four significant figures.
(2)

(ii) Two of the peaks in the mass spectrum of chlorine, Cl2, are at m/e 70 and 74.      Identify the species giving rise to these peaks.
(2)
70
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74
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(iii) What is the m/e value of the other peak that you would expect to see in this region of the mass spectrum and the identity of the species giving rise to it? 
(2)
Value
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Species
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(Total for question = 8 marks)

Unit 1 - Jan 2013
Q11.
Hydrogen has three isotopes, 1H, known as protium, 2H, deuterium, and 3H, tritium.
(a)  In terms of sub-atomic particles, give the similarities and differences between atoms of these three isotopes of hydrogen.
(3)
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(b)  When a nitrogen atom collides with a high energy neutron, one atom of tritium and one atom of another element are formed.  Complete the equation below.
(1)

(c)  Tritium-deuterium gas, consisting of molecules each containing one deuterium atom and one tritium atom, is used in some nuclear warheads.  Typically, each warhead has about 4.0 g of the gas added.
(i)   Calculate the number of moles of tritium-deuterium in 4.0 g.
(2)

(ii)   Calculate the volume, in cm3, of 4.0 g of tritium-deuterium gas. [Molar volume of a gas under these conditions = 24 000 cm3 mol−1]
(1)

(d)  Tritium is not usually included in calculations of the relative atomic mass of hydrogen, because it is radioactive and has a relatively short half-life. Calculate the relative atomic mass of hydrogen with the following isotopic composition.  Give your answer to four decimal places.
(2)

(e)  The electronic energy levels in hydrogen are shown below.

(i)   Mark on the energy level diagram, with an arrow, the transition that represents the ionization energy of hydrogen.
(1)
(ii)   In some versions of the Periodic Table, hydrogen is placed in the same group as sodium.  Give the electronic configurations for both a hydrogen atom and a sodium atom, using the s and p notation. Use these electronic configurations to suggest why this is a reasonable grouping.
(2)
H
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Na
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*(f)  Which element in the Periodic Table has the highest first ionization energy?  Justify your answer.
(3)
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 (Total for question = 15 marks)

Q12.
An isotope of an element, atomic number z, has mass number 2z + 4. How many neutrons are in the nucleus of the element?
   A     z + 4
   B     z + 2
   C     z
   D     4
(Total for question = 1 mark)

Unit 1 - Jun 2013
Q13.
Bromine has two isotopes with relative isotopic masses 79 and 81. Which of the following values for mass/charge ratio could correspond to a peak in the mass spectrum of bromine, Br2? You should assume the ions detected have a single positive charge.
   A    79.9
   B    80
   C    159
   D    160
(Total for Question = 1 mark)

Q14.
(a)  In a mass spectrometer being used to determine relative atomic masses, gaseous atoms are ionized. The ions are then accelerated and deflected before being detected.
(i)  Explain how atoms are ionized in a mass spectrometer.
(1)
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 (ii)  How are the ions accelerated in a mass spectrometer?
(1)
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(iii)  How are the ions deflected in a mass spectrometer?
(1)
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(b)  The following data were obtained from the mass spectrum of a sample of platinum.

Calculate the relative atomic mass of platinum in this sample. Give your answer to one decimal place.
(2)

(c)  In which block of the Periodic Table is platinum found?
(1)
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(d)  Most solids exist as lattice structures.
(i)  Complete the table, using a tick () if the substance conducts electricity or a cross () if the substance does not conduct electricity.
(2)

*(ii)  Explain the electrical conductivities of sodium and of sodium oxide in the solid and liquid states.
(3)
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(Total for Question = 11 marks)
Q15.
Which of the following represents a pair of isotopes?

(Total for Question = 1 mark)

Q16.
The radioactive isotope iodine-131,  I, is formed in nuclear reactors providing nuclear power. Naturally occurring iodine contains only the isotope,  I.
(a)  Complete the table to show the number of protons and neutrons in these two isotopes.
(2)

(b)  When iodine-131 decays, one of its neutrons emits an electron and forms a proton. Identify the new element formed by name or symbol.
(1)
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(c)  The problem with radioactive iodine is that it accumulates in humans in the thyroid gland. Its absorption can be reduced by taking an appropriate daily dose of a soluble iodine compound.
Suggest a suitable iodine compound which could be used.
(1)
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(d)  Nuclear power stations are often proposed as suitable alternatives to those burning coal, gas or oil.
Suggest a country where, because of its location, the dangers of nuclear power may outweigh the advantages. Justify your answer.
(1)
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(Total for Question = 5 marks)
Unit 1 - Jun 2014
Q17.
The correct sequence for the processes that occur in a mass spectrometer is
   A    vaporization, ionization, acceleration, deflection and detection.
   B    vaporization, acceleration, ionization, deflection and detection.
   C    ionization, vaporization, acceleration, deflection and detection.
   D    ionization, vaporization, deflection, acceleration and detection.
(Total for question = 1 mark)
Q18.
Which of the following species contains the same number of electrons as neutrons?

(Total for question = 1 mark)
Q19.
Naturally occurring samples of potassium contain three isotopes, 39K, 40K and 41K.
(a)  The isotopes can be separated in a mass spectrometer.
(i)  In the diagram below, particles are ionized at A and detected at D.

Name the processes occurring in the mass spectrometer at B and C.
(2)
B  ...................................................................................................................................... 
C  ...................................................................................................................................... 
(ii)  A sample of potassium has the following composition.

Calculate the relative atomic mass of this sample of potassium, giving your answer to two decimal places.
(2)

(iii)  Complete the table below to show the numbers of sub-atomic particles in an atom of each of the isotopes 39K and 41K.
(1)

(iv)  Complete the electronic configuration for an atom of 39K.
(1)
1s2 ........................................................................................................................... 

(v)  Why is potassium placed after argon in the Periodic Table, even though it has a smaller relative atomic mass?
(1)
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*(vi)  Explain why a potassium ion is smaller than a potassium atom.
(2)
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(b)  The type of bonding in potassium is metallic.
Draw a labelled diagram to illustrate the metallic bonding in potassium.
(2)

(c)  The graph shows the variation of first ionization energy with atomic number for six successive elements in the Periodic Table, including potassium. The letters used to label the elements are not their symbols.

(i)  Define the term first ionization energy.
(3)
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(ii)  Identify, with a reason, which element is potassium.
(2)
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(Total for question = 16 marks)

Q20.
Nickel is an element in the d-block of the Periodic Table.
(a)  Complete the electronic configuration of a nickel atom using the s, p, d notation.
(1)
1s2 .................................................................................................................... 

(b)  A sample of nickel is made up of three isotopes. The percentage abundances are shown in the table below.

Calculate the relative atomic mass of nickel. Give your answer to two decimal places.
(2)

(c)  Nickel reacts with carbon monoxide, CO, to give the compound nickel carbonyl, Ni(CO)4.
Ni(s) + 4CO(g) → Ni(CO)4(g)
(i)  Calculate the volume of carbon monoxide, in dm3, measured at room temperature and pressure, that is required to react completely with 5.87 g of nickel.
[Relative atomic mass: Ni = 58.7 
Molar volume of a gas = 24 dm3 mol−1 at room temperature and pressure.]
(3)

(ii)  Calculate the number of carbon monoxide molecules present in the volume of gas you have calculated in (c)(i). 
[The Avogadro constant, L = 6.02 × 1023 mol−1]
(1)

(d)  Nickel(II) nitrate, Ni(NO3)2, can be made by several different methods.
Method 1
Nickel(II) oxide, NiO, was reacted with dilute nitric acid according to the equation
NiO(s) + 2HNO3(aq) → Ni(NO3)2(aq) + H2O(l)
(i)  Calculate the volume of 2.00 mol dm−3 dilute nitric acid, in cm3, that was required to exactly neutralize 1.494 g of nickel(II) oxide.
Use the relative atomic masses: Ni = 58.7, O = 16.0
(3)

Method 2
A volume of 25.0 cm3 of 2.00 mol dm−3 nitric acid, HNO3, was transferred to a beaker. Solid nickel(II) carbonate, NiCO3, was added until it was in excess.
(ii)  Why was excess nickel(II) carbonate used?
(1)
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(iii)  Why must the beaker be much larger than the volume of acid used?
(1)
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(iv)  Write a balanced equation for the reaction between nickel(II) carbonate and dilute nitric acid, including state symbols.
(2)

*(v)  For Method 2, describe the practical steps that you would take to obtain pure dry crystals of hydrated nickel(II) nitrate, Ni(NO3)2.6H2O, from a mixture of nickel(II) nitrate solution and unreacted solid nickel(II) carbonate.
(4)
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(Total for question = 18 marks)

Q21.
This question concerns the Periodic Table.
(a)  An atom of argon has mass number 40. Complete the table below showing the numbers of sub-atomic particles in this atom of argon. Use the Periodic Table as a source of data.
(1)

(b)  An atom of potassium has mass number 39. Explain why argon is placed before potassium in the modern Periodic Table.
(1)
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(c)  In the context of the Periodic Table, explain what is meant by the term periodicity.
(2)
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(d)  The graph shows the variation in melting temperatures of the elements across Period 3 (Na to Ar) of the Periodic Table.

(i)  Name one of the elements above that is composed of simple molecules at room temperature and pressure.
(1)
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(ii)  Silicon has a giant atomic structure. Explain how this structure results in the high melting temperature shown on the graph.
(2)
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(iii)  Explain why the melting temperature of magnesium is higher than that of sodium.
(3)
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(Total for question = 10 marks)