Syllabus Edition

First teaching 2023

First exams 2025

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The Periodic Table: Classification of Elements (HL IB Chemistry)

Exam Questions

6 hours98 questions
11 mark

Which of the following statements describes first ionisation energy?

  • The energy required to remove one mole of electrons from one mole of gaseous atoms
  • The energy required to remove the outermost electron from each atom in one mole of gaseous atoms
  • The energy required to remove the outermost electron from each atom in one mole of atoms
  • The energy required to produce one mole of ions from one mole of gaseous atoms

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21 mark
Sodium sulfide, Na2S, is a reactive yellow solid, produced when sodium and sulfur react together.
How do the ionic radius and atomic radius of sodium compare with those of sulfur?

  ionic radius atomic radius
A sodium < sulfur  sodium < sulfur 
B sodium < sulfur  sodium > sulfur
C sodium > sulfur  sodium > sulfur 
D sodium > sulfur  sodium < sulfur

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    31 mark

    Which property below decreases generally across the second period?

    • Atomic number

    • Atomic radius

    • Electronegativity

    • Ionisation energy

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    41 mark

    The trends in three physical properties of the elements of period 3 are shown in the graphs

     q4_3-1_periodic-table--periodic-trends-ib_sl_easy

    Which physical property is not illustrated?

    • Electrical conductivity 

    • Atomic radius

    • Melting point 

    • First ionisation energy

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    51 mark

    This question refers to isolated gaseous species.

    The species O2-, Ne and Mg2+ are isoelectronic.

    In which order do their radii increase?

      Smallest rightwards arrow with blank on top Largest
    A Mg2+

    O2-

    Ne
    B Ne

    O2-

    Mg2+

    C Mg2+

    Ne

    O2-

    D O2- Ne Mg2+

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      61 mark

      Which graph correctly shows the electronegativity of the elements Na, Mg, Al and Si, from period 3, plotted against their first ionisation energies?

      N_bcASI0_q7_3-1_periodic-table--periodic-trends_ib_sl_easy

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        71 mark

        Which period 3 element from sodium to silicon, has the largest atomic radius?

        • Magnesium

        • Sodium

        • Silicon

        • Aluminium

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        81 mark

        What is the correct classification for the element zirconium, Zr?

        • s block

        • d block

        • f block

        • p block

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        91 mark

        What happens to the pH of water when magnesium oxide is dissolved into it?

        • The pH increases, because MgO is acidic

        • The pH decreases, because MgO is basic

        • The pH increases, because MgO is basic

        • Nothing happens because MgO is neutral

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        101 mark

        The Group II metals have higher melting points than the Group I metals.

        Which factors result in Group II metals having higher melting points?

        1. Group II metals have higher first ionisation energy than the corresponding group I metal
        2. there are smaller interatomic distances in the metallic lattices of the Group II metals
        3. more electrons are available from each Group II metal atom for metallic bonding in the lattice

        • I only 

        • I and II only 

        • II and III only 

        • I, II and III

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        111 mark

        What happens when iodine is bubbled through aqueous potassium bromide?

        • Iodine is oxidised to iodide ions

        • Potassium bromide is reduced to bromine

        • Bromide ions are oxidised to bromine

        • No reaction occurs

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        121 mark

        The halogens exist as diatomic molecules, X2.

        Descending down Group 17 from chlorine to iodine the boiling points of the elements increase.

        Which statement explains this trend?

        • The permanent dipole in the X2 molecule increases as the group is descended

        • The X–X bond strength increases as the group is descended

        • The electronegativity of X decreases as the group is descended 

        • The number of electrons in each X2 molecule increases as the group is descended 

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        131 mark

        How do the strengths of the forces between molecules, and the bonds within molecules, vary going down Group 17 from chlorine to bromine to iodine? 

          strength of London dispersion forces strength of covalent bonds
        A increase increase
        B decrease increase
        C increase decrease
        D decrease decrease

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          141 mark

          Most non-metallic oxides can be described as

          • Ionic and alkaline

          • Covalent and alkaline

          • Covalent and acidic

          • Ionic and acidic

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          151 mark

          Which of the options below correctly contains a basic, acidic and amphoteric oxide?

          • K2O, SrO, Al2O3

          • BeO, Al2O3, Br2O

          • Al2O3, SiO2, P4O10

          • P4O10, SO3, F2O

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          161 mark

          Which pair of elements reacts most readily?

          • Li + Br2

          • Li + Cl2

          • K + Br2

          • K + Cl2

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          171 mark

          Chlorine is a greenish-yellow gas, bromine is a dark red liquid, and iodine is a dark grey solid.

          Which property most directly causes these differences in volatility?

          • The halogen–halogen bond energy

          • The number of neutrons in the nucleus of the halogen atom

          • The number of outer electrons in the halogen atom

          • The number of electrons in the halogen molecule

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          181 mark

          Which property increases down group 1 from lithium to caesium?

          • Chemical reactivity

          • First ionisation energy

          • Melting point

          • Electronegativity

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          191 mark

          Which of the following are properties of transition metals?

          1. They have variable oxidation states
          2. They can behave as catalysts
          3. They can have magnetic properties

          • I and II only

          • I and III only

          • II and III only

          • I, II and III

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          201 mark

          Which of the following are factors which affect the colour of a transition metal ion complex?

          1. The identity of the metal ion
          2. The oxidation state of the metal ion
          3. The number of neutrons in the metal ion
          • I and II only

          • I and III only

          • II and III only

          • I, II and III

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          211 mark

          What is the abbreviated electron configuration of the nickel(II) ion, Ni2+ ?

          • [Ar] 3d8

          • [Ar] 4s3d6

          • [Ar] 4s2 3d8

          • [Ar] 4s1 3d7

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          11 mark

          Which statement correctly describes the trend in metallic radius in Group I elements
          Na to Rb?

          1. Increases moving down the group
          2. Increases moving down due to the addition of electron shells
          3. Decreases moving down due to increasing nuclear forces

          • I and II only  

          • I and III only  

          • II and III only 

          • I, II and III

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          21 mark

          The Period 4 elements gallium (Ga), germanium (Ge), arsenic (As) and selenium (Se) are the elements directly below aluminium, silicon, phosphorus and sulfur in the Periodic Table.

          The properties of each Period 4 element resemble those of the Period 3 element directly above it.

          Which period 4 elements form oxides that dissolve in water to give an acidic solution?

          • Ga and Ge 

          • Ge and Se

          • As and Se 

          • Se only

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          31 mark

          Non-metallic elements in the p block can have the following two properties:

          • property 1: atoms with no paired electrons in 3p
          • property 2: have an oxide that can form a strong acid in water

          Which properties do phosphorus and sulfur have? 

            sulfur phosphorus
          A

          2 only

          1 and 2 

          B

          1 and 2 

          2 only

          C

          1 and 2 

          1 and 2

          D 2 only 1 only

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            41 mark

            Which graph correctly illustrates a trend found in the halogen group?q4_medium_mcq_3-2_ib-chemistry-sl

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              51 mark

              Which of the following statements is true as you move down Group I?

              • The first ionisation energy increases

              • The atomic radius increases

              • The melting point increases

              • The reaction with water becomes less vigorous

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              61 mark

              Which statement is not correct?

              • Caesium has a lower first ionisation energy than rubidium

              • Rubidium reacts less violently with water than potassium

              • Potassium has a larger atomic radius than sodium

              • Sodium melts at a higher temperature than caesium

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              71 mark

              When a student dissolved the oxides of calcium and tellurium in water, the resulting solutions were tested with litmus paper. It would be seen that:

              • Calcium turns litmus paper blue, but tellurium turns litmus paper red

              • Calcium and tellurium both turn litmus paper red

              • Calcium turns litmus paper red, but tellurium turns litmus paper blue

              • Calcium and tellurium both turn litmus paper blue

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              81 mark

              Which of the following statements about strontium oxide and lithium oxide are true?

              1. Strontium oxide has pH > 7
              2. Lithium oxide is basic
              3. A solution containing both oxides would turn universal indicator red 
              • I and II only

              • I and III only 

              • II and III only

              • I, II and III

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              91 mark

              Which statements are correct?

              1. Fluorine will react with potassium chloride solution to produce chlorine.
              2. Iodine will react with sodium chloride solution to produce chlorine.
              3. Bromine will react with lithium iodide solution to produce iodine.
              • I and II only

              • I and III only

              • II and III only

              • I, II and III

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              101 mark

              Which is a characteristic property of sodium oxide?

              • It turns moist litmus paper blue

              • It turns moist litmus paper red

              • When it dissolves in distilled water it forms a solution with pH less than 7

              • It reacts with magnesium metal

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              111 mark

              Electron configurations for atoms of different elements are shown below. 

              Which electron configuration represents the element with the largest first ionisation energy?

              • 1s22s22p63s2

              • 1s22s22p63s23p4

              • 1s22s22p63s23p6

              • 1s22s22p63s23p64s2

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              121 mark

              Which graph correctly shows the relative melting points of period 3 elements plotted against their relative electronegativities?

              q5_3-1_periodic-table--periodic-trends_ib_sl_medium

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                131 mark

                For the following pairs, which has the greatest difference in size?

                • Li and Cl

                • Na and Br

                • Li+ and Br-

                • Na+ and Cl-

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                141 mark

                Elements X and Y are Period 3 elements that react together to form compound Z. Element X has the second smallest atomic radius in Period 3. Apart from argon, there is only one element in Period 3 which has a lower melting point than element Y.

                Which compound could be Z?

                • Na2S

                • MgS

                • MgCl 2

                • PCl 3

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                151 mark

                Which of these elements would form the largest ion with a noble gas electron configuration?

                • Gallium

                • Bromine

                • Arsenic

                • Rubidium

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                161 mark

                The order of the elements in the periodic table is

                • according to relative atomic mass

                • by nuclear charge

                • by reactivity

                • in order of electronegativity

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                171 mark

                Which complex is likely to be colourless?

                • [Zn(H2O)6]Cl2

                • [NH4]2[Fe(H2O)6][SO4]2

                • K3[Co(CN)6]

                • [Ni(NH3)6][BF4]2

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                181 mark

                Part of the spectrochemical series is shown. 

                I< Cl < H2O < NH3 

                Which statement can be correctly deduced from the series?

                • H2O increases the p–d separation more than Cl - 

                • H2O increases the d–d separation more than Cl -

                • A complex with NH3 is more likely to be blue than that with Cl - 

                • Complexes with water are always blue 

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                11 mark

                G and J are oxides of different Period 3 elements.

                If one mole of J is added to water, the solution formed is neutralised by exactly one mole of G.

                What could be the identities of G and J? 

                  G J
                A Na2O SO3
                B Na2O P4O10
                C Al2O3 SO3
                D Al2O3 P4O10

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                  21 mark

                  An element is found in Group I of the Periodic Table, below lithium and sodium. From this information it is likely that the element is a metal with 

                  • A high melting point and which reacts slowly with water

                  • A low melting point and which reacts vigorously with water

                  • A high melting point and which reacts vigorously with water

                  • A low melting point and which reacts slowly with water

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                  31 mark

                  A student opens a freezer in their lab to remove a test tube containing an oxide of a Period 3 element. The oxide is a solid and forms a solution with a low pH when dissolved in water. 

                  Identify the element.

                  • S

                  • Al

                  • Si

                  • Mg

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                  41 mark

                  The x-axis of the graph below is the atomic number of the elements in Period 3.

                  q4_3-2_hard_mcq_ib-chemistry-sl

                  Which variable could represent the y-axis?

                  • Melting point 

                  • Electronegativity

                  • Ionic radius

                  • Atomic radius

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                  51 mark

                  The first ionisation energies and reactions with water for sodium and caesium are compared below.

                  Which set of statements, comparing sodium and caesium, are correct?

                   

                  Na first ionisation energy

                  Cs first ionisation energy

                  Na reaction with water

                  Cs reaction with water

                  A

                  Lower

                  Higher

                  Faster

                  Slower

                  B

                  Lower

                  Higher

                  Slower

                  Faster

                  C

                  Higher

                  Lower

                  Faster

                  Slower

                  D

                  Higher

                  Lower

                  Slower

                  Faster

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                    61 mark

                    An element Z has the same oxidation state as a common iron ion but the Z ion has the same number of electrons as Ne . An oxide of element Z reacts with a strong acid to produce a chloride salt but does not dissolve in water.

                    What is the correct identity of element Z?

                    • Magnesium

                    • Silicon

                    • Sodium

                    • Aluminium

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                    71 mark

                    X, Y and Z represent different halogens. The table shows the results of nine experiments in which aqueous solutions of X2, Y2 and Z2 were separately added to separate aqueous solutions containing X-, Y- and Z- ions.

                     

                    X- (aq)

                    Y- (aq)

                    Z- (aq)

                    X2 (aq)

                    Y2 (aq)

                    Z2 (aq)

                    no reaction

                    X2 formed

                    X2 formed

                    no reaction

                    no reaction

                    no reaction

                    no reaction

                    Z2 formed

                    no reaction

                    What is the correct order to show the decreasing strength of the ions X-, Y- and Z-  as reducing agents?

                    • X- > Y- > Z- 

                    • X- > Z- > Y- 

                    • Y- > Z- > X- 

                    • Z- > X- > Y- 

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                    81 mark

                    A dark red/brown solution is formed when a halide salt containing the halide ion Y- reacts with aqueous chlorine. This solution then forms a violet solution when shaken with a cyclohexane solution.

                    What is halogen, Y?

                    • Fluorine

                    • Iodine

                    • Iodide

                    • Bromide

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                    91 mark

                    A student reacts the most basic period 3 oxide with the strongest acid formed from a period 3 element.

                    Identify the correct equation for this reaction

                    • Na2O + 2HCl  → 2NaCl  + H2O

                    • 3MgO + 2H3PO4 → Mg3(PO4)2 + 3H2O

                    • Na2O + H2SO4 → Na2SO4 + H2O

                    • MgO + HCl → MgCl2 + H2O

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                    10
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                    1 mark

                    Which of the following is the most stable common oxidation state of manganese?

                    • Mn+

                    • Mn2+

                    • Mn3+

                    • Mn4+

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                    11
                    Sme Calculator
                    1 mark

                    Which metal sulfate solution is coloured?

                    • ZnSO4 (aq)

                    • NiSO4 (aq)

                    • MgSO(aq)

                    • Sc2(SO4)3 (aq)

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                    12
                    Sme Calculator
                    1 mark

                    Which complex has the greatest d orbital splitting?

                      Complex Oxidation state of metal Colour of complex
                    A. [Fe(H2O)6]3+ +3 orange
                    B. [CoCl4]2- +4 blue
                    C. [Cr(OH)6]3- +3 green
                    D. [Cr(NH3)6]3+ +3 violet

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                      131 mark

                      The species Cl-, K+ and Ar are isoelectronic. This means that they have the same number of electrons. 

                      In which order do their radii decrease?

                        largest smallest

                      A

                      K+ Cl

                      Ar

                      B

                      Cl

                      Ar

                      K+

                      C

                      K+

                      Ar Cl
                      D Ar K+ Cl

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                        141 mark

                        The atomic radius of the elements decreases across period 3. Which of the following statements explain(s) this phenomenon? 

                        I
                        electrons shells are added across Period 3 which increases the nuclear force of attraction
                        II
                        the nuclear charge increases across Period 3 due to increasing atomic number
                        III
                        there is a greater force of attraction between the nucleus and the electrons
                        • I and II only 

                        • I, II and III

                        • II and III only 

                        • I only

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                        151 mark

                        The first ionisation energy of beryllium is higher than the first ionisation energy of boron. 

                        Which statement explains why?

                        • boron has a full outer shell

                        • boron has a larger atomic radius than beryllium

                        • beryllium has a more stable electronic configuration

                        • the atomic number of beryllium is higher than boron

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                        161 mark

                        The electronic configurations of four different atoms are shown. 

                        Which atom has the highest first ionisation energy?

                        • 1s2 2s2 2p6 3s2

                        • 1s2 2s2 2p4

                        • 1s2 2s2 2p6 

                        • 1s2 2s2 

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                        171 mark

                        Sir Humphrey Davy discovered the elements magnesium, boron, sodium and calcium. 

                        Which of the elements Sir Davy discovered has the third lowest first ionisation energy in its Period and the third smallest atomic radius in its Group?

                        • magnesium

                        • boron

                        • sodium

                        • calcium

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                        181 mark

                        Which of the following pairs does the second element have a higher 1st ionisation energy than the first element?

                         

                        First element

                        Second element

                        A

                        Mg

                        Al

                        B

                        N

                        O

                        C

                        Ne

                        Na

                        D

                        K

                        Na

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                          191 mark

                          Shown on the graph are the relative values of the first ionisation energies of four elements that have consecutive atomic numbers. One of the elements reacts with hydrogen to form a covalent compound with formula HX. 

                          Which element could be X?

                          q7_3-1_periodic-table--periodic-trends_ib_-sl_hard

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                            201 mark

                            Below are four statements about energy levels and electrons. Which is the correct statement?

                            • 18 is the maximum number of electrons in the 4th energy level

                            • 10 is the maximum number of electrons in one d orbital

                            • Yttrium is the first element with an electron in an f subshell

                            • In a main energy level, the subshell with the highest energy is f

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                            211 mark

                            Element J has a lower first ionisation energy and higher melting point than the element preceding it in the periodic table. 

                            Its ion is isoelectronic with argon. 

                            What is the identity of element J?

                            • Na

                            • S

                            • P

                            • Al

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                            221 mark

                            Which statement about electron affinity and electronegativity is correct?

                            • Electron affinity increases down a group, but electronegativity decreases

                            • Electron affinity decreases down a group, but electronegativity increases

                            • Electron affinity and electronegativity both decrease down a group

                            • There is no clear trend in electron affinity down a group but electronegativity decreases

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