2.3.3Additional lessons
Physical Properties of Transition Elements (HL) — IB Chemistry HL Revision Notes & Topical Questions
5 min read 5 parts Lesson 44 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 5Transition Elements
Transition metals combine the typical properties of metals with extra strength and density.
Definition
- Definition A transition element forms at least one ion with a partially filled d subshell.
Location
- Location They are found in the d block, between groups 2 and 13, in periods 4 to 7.
Exceptions
- Exceptions Zinc forms only Zn²⁺ with a full d subshell, so it is usually not classed as a transition element.
Metallic bonding
- Metallic bonding Both 4s and 3d electrons contribute to the delocalised electrons in the first row.
Section 2 of 5Typical Physical Properties
Typical Physical Properties
High melting points
- High melting points More delocalised electrons give stronger metallic bonding, so iron melts at 1538 °C and copper at 1085 °C.
High density
- High density Their atoms are small and heavy, so densities are high, such as 7.87 g cm⁻³ for iron.
Hardness and strength
- Hardness and strength Strong metallic bonds make them hard and tough, so they are used in construction.
Electrical conductivity
- Electrical conductivity Delocalised electrons make transition metals good electrical and thermal conductors.
Section 3 of 5Comparison With Group 1 and 2
1
Sodium has a density of 0.97 g cm⁻³ and melts at 98 °C, whereas iron has 7.87 g cm⁻³ and melts at 1538 °C.
2
Magnesium has a density of 1.74 g cm⁻³, much lower than copper at 8.96 g cm⁻³.
3
The stronger bonding arises because transition metals provide more delocalised electrons from both s and d subshells.
4
Zinc melts at only 420 °C because its filled d subshell contributes few electrons to bonding.
| Metal | Density / g cm⁻³ | Melting point / °C |
|---|---|---|
| Na | 0.97 | 98 |
| Fe | 7.87 | 1538 |
| Cu | 8.96 | 1085 |
| Zn | 7.14 | 420 |
Section 4 of 5Other Features
Malleable and ductile
- Malleable and ductile Layers slide while delocalised electrons keep the structure bonded.
Magnetism
- Magnetism Iron, cobalt and nickel are ferromagnetic, which is unusual among the elements.
Mercury
- Mercury A group 12 metal that is liquid at room temperature, an exception to the high melting trend.
Uses
- Uses Iron in steel, copper in wiring and titanium in aircraft depend on these properties.
Section 5 of 5Exam Checklist & Tips
2.3.3 – Key Points for the Exam
- Transition element An element that forms at least one ion with an incomplete d subshell.
- d block Elements whose highest energy electrons are being added to a d subshell.
- Ferromagnetic Strongly attracted to magnets and able to become magnetised.
- Density Mass per unit volume of a substance.
Common Mistakes
- Treating zinc as a typical transition metal with a high melting point.
- Saying transition metals have weak metallic bonding.
- Forgetting the 4s electrons contribute as well as the 3d electrons.
- Confusing the d block with the transition elements; they are not exactly the same.
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