3.1.9Additional lessons
Characteristic Properties of Transition Elements (HL) — IB Chemistry HL Revision Notes & Topical Questions
5 min read 5 parts Lesson 56 of 172
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Section 1 of 5What Makes an Element Transition
Definition
- Definition A transition element forms at least one ion with a partially filled d sub-level.
Scandium
- Scandium Scandium forms only Sc³⁺ with the configuration [Ar], so there are no d electrons and it is not a typical transition element.
Zinc
- Zinc Zinc forms only Zn²⁺ with a full 3d¹⁰ sub-level, so it is also excluded.
Physical properties
- Physical properties Transition metals tend to be hard, dense, strong and to have high melting points with good electrical conductivity.
Cause
- Cause Close energies of 4s and 3d electrons allow several electrons to be lost or shared, giving similar chemistry across a row.
Section 2 of 5Characteristic Properties
1
Variable oxidation states arise because 4s and 3d electrons can be lost in different numbers, as in Fe²⁺ and Fe³⁺.
2
Compounds are often coloured because d electrons can absorb visible light when ligands split the d sub-level.
3
Many form complex ions by accepting lone pairs from ligands, as in [Cu(H₂O)₆]²⁺ and [Fe(CN)₆]³⁻.
4
They show catalytic activity, for example iron in the Haber process, vanadium(V) oxide in the contact process and nickel in hydrogenation.
5
Unpaired d electrons give paramagnetism, so the substance is attracted into a magnetic field.
| Property | Example |
|---|---|
| Variable oxidation state | Mn: +2, +4, +7 |
| Coloured ion | Cu²⁺(aq) is blue |
| Catalyst | MnO₂ for H₂O₂ decomposition |
| Paramagnetic | Fe³⁺, with 5 unpaired electrons |
Section 3 of 5Comparing with s-block Metals
Comparing with s-block Metals
Oxidation states
- Oxidation states Group 1 and 2 metals have one fixed positive oxidation state, but transition metals show several.
Colour
- Colour Compounds of Group 1 and 2 metals are normally white or colourless, but transition ions are often vividly coloured.
Catalysts
- Catalysts Heterogeneous catalysts adsorb reactants on the surface, while homogeneous ones change oxidation state during reaction.
Magnetism
- Magnetism Ions with all electrons paired are diamagnetic and are slightly repelled by magnetic fields.
Section 4 of 5Worked Example
Question Decide whether Cu²⁺ and Zn²⁺ ions show transition-metal behaviour.
- Copper has atomic number 29 and Cu²⁺ is [Ar] 3d⁹.
- The 3d sub-level of Cu²⁺ is partially filled with nine electrons, so copper is a transition element.
- Zinc has atomic number 30 and Zn²⁺ is [Ar] 3d¹⁰.
- The 3d sub-level is full in every common zinc ion, so zinc is not a transition element.
Answer Cu²⁺ is a transition ion; Zn²⁺ is not
Section 5 of 5Exam Checklist & Tips
3.1.9 – Key Points for the Exam
- Transition element An element that forms at least one ion with a partially filled d sub-level.
- Paramagnetic Attracted into a magnetic field because of unpaired electrons.
- Ligand A species with a lone pair that bonds to a central metal ion by dative bonding.
- Heterogeneous catalyst A catalyst in a different phase from the reactants.
Common Mistakes
- Calling every d-block element a transition element, including Sc and Zn.
- Saying the 3d electrons are lost before the 4s electrons.
- Believing that colour in compounds arises only from impurities.
- Forgetting that Cu⁺ with 3d¹⁰ is colourless.
Last updated:
\n