# Explain why the electrical conductivity of copper is much greater than that of manganese, despite both being transition metals in the same period.

> IB DP Chemistry Higher Level (2023 syllabus) — S2.3 The metallic model · Explain · 4 marks

> Copper has an anomalous electron configuration of [Ar] 3d¹⁰ 4s¹, whilst manganese has the configuration [Ar] 3d⁵ 4s². At 20 °C, copper conducts electricity approximately 50 times better than manganese.

## Mark scheme (4 marks)

1. Metals conduct electricity because delocalised electrons are free to move through the lattice / act as charge carriers.
2. Copper contributes only one valence electron to the delocalised sea (from 4s¹), whereas manganese contributes two (from 4s²), so the difference in conductivity cannot be explained by valence electron count alone; the key factor is the extent of electron scattering.
3. Copper's completely filled 3d subshell (3d¹⁰) produces a spherically symmetric / more uniform ion core, resulting in less scattering of delocalised electrons and therefore lower resistance.
4. Therefore copper has a much lower electrical resistivity / higher conductivity because the delocalised electrons experience less scattering as they move through the lattice.

## Key terms

- [electrical conductivity](https://www.gradenine.co.uk/glossary/electrical-conductivity)

## Related

- [Revision notes for IB DP Chemistry Higher Level (2023 syllabus)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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