Atoms and small molecules are extremely small. The table shows the approximate sizes of some particles and objects.
| Particle or object | Approximate size in m |
|---|---|
| hydrogen atom | 1 × 10-10 |
| methane molecule | 4 × 10-10 |
| human hair (width) | 1 × 10-4 |
Give the size of a methane molecule in nanometres (nm). 1 nm = 1 × 10-9 m
Calculate how many times wider a human hair is than a methane molecule.
Give the number of orders of magnitude difference between the size of a hydrogen atom and the width of a human hair.
Suggest why a methane molecule is larger than a hydrogen atom.
Nanoparticles are between 1 nm and 100 nm in size. A student says that a methane molecule is a nanoparticle. Explain whether the student is correct.
53 exam-style questions on Edexcel GCSE Chemistry 2.4 Covalent bonding, covering 2.4.1 Covalent bonding and simple molecules. Each one has a worked solution and a mark scheme showing where the marks go.