# Nanoparticles are increasingly being used in sunscreens and in medical drug delivery systems. Describe two properties of nanoparticles that make them useful in these applications, and for each property explain why it arises.

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

> Nanoparticles are particles with diameters between 1 nm and 100 nm. Scientists are developing new uses for nanoparticles in medicine and cosmetics because of the special properties they possess compared to bulk materials.

## Mark scheme (4 marks)

1. Nanoparticles have a very large surface area to volume ratio (compared to bulk material of the same substance)
2. This large surface area to volume ratio means more of the substance is exposed / available to interact, making nanoparticles more reactive or more effective at absorbing UV radiation / delivering drugs to target cells
3. Nanoparticles can exhibit different / new properties compared to the bulk material of the same substance (e.g. different optical, chemical or physical properties)
4. These different properties arise because at the nanoscale the size of the particles is comparable to the scale of atoms/molecules, so quantum or surface effects become significant, meaning behaviour differs from a bulk sample

## Key terms

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

## Related

- [Revision notes for Edexcel GCSE Chemistry (1CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/nanoparticles-are-increasingly-being-used-in-86b0d158) · Published by Druglandscape Ltd.