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IB Chemistry HL 3.1 The Periodic Table Questions

Practise IB Chemistry HL 3.1 with evidence-led questions on periodicity, trends, elements and properties.

Syllabus
First assessment 2025
Course
Chemistry HL
Level
HL

Exam points

  • Use periodic position and electron configuration to compare elements and predict chemical behaviour.
  • Explain periodic trends using nuclear charge, shielding, sublevel energy and electron pairing, including ionization-energy exceptions.
  • Use group and displacement evidence to predict redox behaviour and balance the supporting equations.
  • Classify oxides and elements along the metal/non-metal continuum using structure, reactions and pH evidence.
  • Determine oxidation states and explain transition-element trends, variable oxidation states and colour using electron structure.

Covered syllabus points

3.1.1—Organization3.1.2—Electron configuration and position3.1.3—Periodicity3.1.4—Group trends3.1.5—Metal/non-metal continuum3.1.6—Oxidation states3.1.7 (HL)—IE discontinuities3.1.8 (HL)—Transition element properties3.1.9 (HL)—Variable oxidation states3.1.10 (HL)—Transition element colors

Learn this topic

Study 3.1 The periodic table conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

Question 1

[Maximum number: 5]

Lithium and boron are elements in period 2 of the periodic table. Lithium occurs in group 1 (the alkali metals) and boron occurs in group 3. Isotopes exist for both elements.

Question (a)

(a)

Distinguish between the terms group and period.

[ 1 ]

Question (b)

(b)

State the other most common ion of cobalt.

[ 1 ]

Question (c)

(c)

Explain why the complex [Co(NH3)6]Cl3\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3} is coloured.

[ 3 ]

Question 2

[Maximum number: 6]

Iron rusts in the presence of oxygen and water. Rusting is a redox process involving several steps that produces hydrated iron(III) oxide, Fe2O3∙nH2O\mathrm{Fe}_{2} \mathrm{O}_{3} \bullet \mathrm{nH}_{2} \mathrm{O}, as the final product. The half-equations involved for the first step of rusting are given below.

Half-equation 1: Fe(s)→Fe2+(aq)+2e−\quad \mathrm{Fe}(\mathrm{s}) \rightarrow \mathrm{Fe}^{2+}(\mathrm{aq})+2 \mathrm{e}^{-}

Half-equation 2: O2(aq)+4e−+2H2O(l)→4OH−(aq)\quad \mathrm{O}_{2}(\mathrm{aq})+4 \mathrm{e}^{-}+2 \mathrm{H}_{2} \mathrm{O}(\mathrm{l}) \rightarrow 4 \mathrm{OH}^{-}(\mathrm{aq})

Question (a)

(a)

Identify the oxidation number of each atom in the three species in half-equation 2.

Figure for Question (a) — IB Chemistry HL
[ 2 ]

Question (b)

(b)

State the relationship between the electron arrangement of an element and its group and period in the periodic table.

[ 2 ]

Question (c)

(c)

Transition metals and their compounds often catalyse reactions. The catalyzed decomposition of hydrogen peroxide by CuO is an example. State two other examples of catalyzed reactions giving the transition metal or its compound acting as catalyst.

[ 2 ]

Question 3

[Maximum number: 4]

Iron may be extracted from iron (II) sulfide, FeS.

Question (a)

(a)

Justify why sulfur is classified as a non-metal by giving two of its chemical properties.

[ 2 ]

Question (b)

(b)

Iron (II) sulfide, FeS, is ionically bonded.

[ 1 ]

Question (i)

(i)

Outline, in terms of their electronic structures, why the ionic radius of the sulfide ion is greater than that of the oxide ion.

[ 1 ]

Question (c)

(c)

The first step in the extraction of iron from iron (II) sulfide is to roast it in air to form iron (III) oxide and sulfur dioxide.

[ 1 ]

Question (i)

(i)

Deduce the change in the oxidation state of sulfur.

[ 1 ]
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