2.3.3 (HL)—Transition elements
- Syllabus
- First assessment 2025
- Objective
- 2.3.3
- Level
- HL
Transition-Element Metallic Properties
HL onlyTransition elements have delocalized d electrons as well as s electrons in their metallic structure. These mobile electrons are attracted to a lattice of positive metal ions.
More delocalized electrons can strengthen the electrostatic attraction, so substantial energy is often needed to disrupt the lattice, helping to explain high melting points. The same mobile electrons carry charge through the solid, explaining electrical conductivity.
Use this as a causal model, not a universal ranking: electron contribution, ion radius and crystal structure vary across the transition series, so melting points need not form a perfectly smooth trend. The chemical reactions of transition elements belong to Reactivity 3.4, not this card.
Explaining Transition-Element Strength
HL onlyAssessment in practice
Representative question
Question 1
[Maximum number: 1]
Suggest why the melting point of vanadium is higher than that of titanium.
vanadium has smaller ionic radius «leading to stronger metallic bonding»
Accept vanadium has «one» more valence electron«s» «leading to stronger metallic bonding». Accept "atomic" for "ionic".
The Metallic Model Summary
Retrieve the model: positive ions attract delocalized electrons; electron mobility explains conductivity and non-directional bonding explains malleability; charge, radius, and d-electron contribution explain strength trends.
A complete property explanation should name the cation lattice, delocalized electrons, and the specific structural change relevant to the property.