Question: In your work description you said that a nano-meter is around ten atoms wide, but don't atoms vary in size as they are made up of different quantities of protons and neutrons and if so do you mean that one nano-meter is the size of two silicon atoms for example?

Serena Corr answered on 24 Jun 2013:

Hi theantihiggs – this is a really good question/comment:

Yes – you are right. I said that that a nanometer was around 10 atoms wide, but that is not exact – just an approximate number. I wanted to convey just how small these kinds of length scales are. You are correct though – if we look at an example of two different elements: fluorine atoms have an atomic radius of 50 picometers (0.05 nanometers) while an atom of silicon has an atomic radius of 110 pm (0.11 nanometers). So, for silicon, you would need approximately 5 atoms to get to 1 nanometer, while for fluorine you would need 10 atoms to reach 1 nanometer across.

I hope that answers your question!