# Gold is a metal that has been used for centuries in jewellery. Scientists have recently developed gold nanoparticles for use in medical treatments. Explain why gold nanoparticles may behave differently compared to a bulk sample of gold, and suggest one reason why gold nanoparticles might be useful in delivering drugs inside the human body.

> Edexcel GCSE Chemistry (1CH0) — 9.2 Bulk and surface properties of matter, including nanoparticles (Chem only) · Explain · 4 marks

> Gold nanoparticles have diameters between 1 nm and 100 nm. A bulk sample of gold appears yellow and is chemically unreactive. Gold nanoparticles, however, can appear red or purple in solution and show increased chemical reactivity.

## Mark scheme (4 marks)

1. Nanoparticles have a much larger surface area to volume ratio than bulk gold
2. The higher surface area to volume ratio means more atoms are exposed / available to interact, leading to different (e.g. chemical or optical) properties
3. Gold nanoparticles are very small / have diameters between 1 nm and 100 nm, so they can enter cells or pass through cell membranes
4. This allows targeted / more effective drug delivery (to specific cells or tumours), reducing side effects or improving treatment

## Key terms

- [nanoparticles](https://www.gradenine.co.uk/glossary/nanoparticles)
- [bulk](https://www.gradenine.co.uk/glossary/bulk)

## Related

- [Revision notes for Edexcel GCSE Chemistry (1CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/gold-is-a-metal-that-has-3409708f) · Published by Druglandscape Ltd.