3.1.8 (HL)—Transition element properties
- Syllabus
- First assessment 2025
- Objective
- 3.1.8
- Level
- HL
Transition-Element Properties
HL only| Evidence | Characteristic property |
|---|---|
| Incomplete d-sublevels | Variable oxidation states and magnetic behaviour |
| d-electron transitions | Coloured compounds |
| Metal/ligand interactions | Complex ions and catalytic behaviour |
| Metallic bonding | High melting points and conductivity |
A transition element has an atom or at least one stable/common ion with a partially filled d subshell. Test the actual configurations: occupying the d block is not sufficient by itself, so species whose relevant atom and common ions are d⁰ or d¹⁰ do not meet the definition merely because of table position. Then connect each claimed characteristic property to electronic or complex-ion evidence.
Check the d subshell in the atom or a common ion: a species with an incomplete d subshell can show unpaired-electron magnetism, variable oxidation states, complex formation and colour. Do not infer every property from the label alone; connect colour to d-level splitting and catalysis to accessible oxidation states or adsorption pathways.
Recognising Transition Chemistry
HL onlyAssessment in practice
Representative question
Question 1
[Maximum number: 1]
Outline, in terms of its electronic structure, what identifies a transition element.
has a partially filled d sub-shell «in a common oxidation state»
The Periodic Table Summary
Retrieve the route: locate an element from configuration, explain periodic and group trends, write oxide/reaction and oxidation-state answers, then connect incomplete d-sublevels to transition properties, ion configurations, and colours.
Check that every trend explanation names its particle-level cause, every equation is balanced, every oxidation state is a formal charge convention, and every transition colour uses absorbed/observed complementarity.