AQA · GCSE · Chemistry
Course version: 8462 · Version from Sept 2018
Students should be able to compare ‘nano’ dimensions to typical dimensions…
Full specification wording
Sizes of particles and their properties: Students should be able to compare ‘nano’ dimensions to typical dimensions of atoms and molecules.
Nanoparticles are particles with at least one dimension in the range 1 to 100 nanometres, where 1 nm = 1 × 10⁻⁹ m.
Checked against the AQA 8462 specification (opens in a new tab) on .
- Point 6 of 6
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Nanoparticles are particles with at least one dimension in the range 1 to 100 nanometres, where 1 nm = 1 × 10⁻⁹ m. Typical atoms are about 0.1 to 0.5 nm across, and small molecules are often around 0.5 to 2 nm across, so a nanoparticle is roughly a few to a few hundred atoms or molecules wide. Fine particles (PM2.5) have diameters between 100 and 2500 nm, while coarse particles (PM10) are larger still, often micrometres across. Nanoparticles sit between individual atoms or molecules and bulk material. Comparing dimensions means using the same unit, usually nanometres, and stating how many atoms or molecules would fit across a nanoparticle.
What earns the marks
- Nanoparticles have at least one dimension between 1 nm and 100 nm.
- One nanometre is 1 × 10⁻⁹ m, so nano dimensions are much smaller than everyday objects.
- Typical atoms are about 0.1 to 0.5 nm across and small molecules are often about 0.5 to 2 nm across.
- A nanoparticle is therefore roughly a few to a few hundred atoms or molecules across, larger than a single atom or small molecule but smaller than fine and coarse particles.
- Comparisons should use the same unit, such as nanometres, and may use a simple ratio or scale factor.
Common mistakes and how to put them right
Treating a nanoparticle as a single atom or molecule.
Put it right: A nanoparticle contains many atoms or molecules and is larger than both.
Mixing up nanometres and metres without converting.
Put it right: Convert using 1 nm = 1 × 10⁻⁹ m before comparing.
Describing nanoparticles as simply very small without giving a scale.
Put it right: Quote the 1 to 100 nm range and compare it with atomic or molecular sizes.
Exam tips
- Quote the 1 to 100 nm range and the value of 1 nm in metres when making a comparison.
- Use a ratio such as a 10 nm particle being about 20 to 100 atoms across, depending on the atom size, to show scale.
- State clearly that nanoparticles are larger than atoms and molecules but smaller than fine and coarse particles.
Try the lesson
The start of the Sizes of particles and their properties: Students should be able to compare ‘nano’ dimensions to typical dimensions of atoms and molecules. lesson, made from checked teaching notes for this specification point.
Have a go first
Which statement correctly compares the size of a nanoparticle with the typical size of an atom?
Listen
Nanoparticles are particles with at least one dimension in the range 1 to 100 nanometres, where 1 nm = 1 × 10⁻⁹ m. Typical atoms are about 0.1 to 0.5 nm across, and small molecules are often around 0.5 to 2 nm across, so a nanoparticle is roughly a few to a few hundred atoms or molecules wide. Fine particles (PM2.5) have diameters between 100 and 2500 nm, while coarse particles (PM10) are larger still, often micrometres across. Nanoparticles sit between individual atoms or molecules and bulk material. Comparing dimensions means using the same unit, usually nanometres, and stating how many atoms or molecules would fit across a nanoparticle. A strong answer earns marks for these points. Nanoparticles have at least one dimension between 1 nm and 100 nm. One nanometre is 1 × 10⁻⁹ m, so nano dimensions are much smaller than everyday objects. Typical atoms are about 0.1 to 0.5 nm across and small molecules are often about 0.5 to 2 nm across. A nanoparticle is therefore roughly a few to a few hundred atoms or molecules across, larger than a single atom or small molecule but smaller than fine and coarse particles. A common slip: Treating a nanoparticle as a single atom or molecule. Instead, a nanoparticle contains many atoms or molecules and is larger than both. Exam tip: Quote the 1 to 100 nm range and the value of 1 nm in metres when making a comparison.
See it
Put it in order
Put these steps in the order they happen.
- 1. Small molecule: often about 0.5 to 2 nm across
- 2. Nanoparticle: at least one dimension 1 to 100 nm
- 3. Atom: about 0.1 to 0.5 nm across
- 4. Coarse particles (PM10): larger still, often micrometres across
- 5. Fine particles (PM2.5): 100 to 2500 nm
Key words
Say what each word means before you turn the card.
Nanoparticles
Try answering aloud or in your head before turning the card.
Nanometre range
Try answering aloud or in your head before turning the card.
Atoms and molecules
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Size comparisons
Try answering aloud or in your head before turning the card.
See every definition
- Nanoparticles
- Particles with at least one dimension in the range 1 to 100 nanometres, sitting between individual atoms or molecules and bulk material.
- Nanometre range
- One nanometre is 1 × 10⁻⁹ m, so nano dimensions are much smaller than everyday objects.
- Atoms and molecules
- Typical atoms are about 0.1 to 0.5 nm across and small molecules are often about 0.5 to 2 nm across.
- Size comparisons
- Comparisons should use the same unit, such as nanometres, and may use a simple ratio or scale factor.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
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