AQA · GCSE · Chemistry
Course version: 8462 · Version from Sept 2018
All substances are made of atoms. An atom is the smallest part of an…
Full specification wording
Atoms, elements and compounds: All substances are made of atoms. An atom is the smallest part of an element that can exist.
This statement establishes the particle model at the atomic scale.
Checked against the AQA 8462 specification (opens in a new tab) on .
- Point 1 of 10
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
This statement establishes the particle model at the atomic scale. Every substance, whether an element, compound or mixture, is built from atoms. An element contains only one type of atom, and that atom is the smallest particle that can still be identified as that element. Atoms are not indivisible in reality, but for GCSE chemistry the key idea is that they are the fundamental building blocks of matter. For example, a piece of copper metal is made of copper atoms; a water molecule contains hydrogen and oxygen atoms. When you write a chemical symbol such as Fe, it represents one atom of iron. The statement also implies that atoms are conserved in chemical reactions, because they are the smallest parts that can exist and cannot be created or destroyed by ordinary chemical means.
What earns the marks
- State that all substances are composed of atoms.
- Define an atom as the smallest part of an element that can exist.
- Recognise that an element contains only one type of atom.
- Use the idea that atoms are the building blocks of all matter, including compounds and mixtures.
- Apply the definition to distinguish between atoms and larger particles such as molecules or ions.
Common mistakes and how to put them right
Confusing atoms with molecules.
Put it right: Use the definition that an atom is the smallest part of an element.
Thinking that atoms can be split in chemical reactions.
Put it right: State that atoms are rearranged, not broken apart, in chemical reactions.
Believing that all atoms are identical.
Put it right: Specify that an atom is the smallest part of a particular element.
Exam tips
- When asked to define an atom, include both 'smallest part' and 'of an element' to secure the mark.
- Use the term 'substance' correctly: it can be an element, compound or mixture, but all are made of atoms.
- If a question asks why atoms are important in chemistry, link to conservation of mass in reactions.
Try the lesson
The start of the Atoms, elements and compounds: All substances are made of atoms. An atom is the smallest part of an element that can exist. lesson, made from checked teaching notes for this specification point.
Have a go first
Which of the following statements correctly describes an atom?
Listen
This statement establishes the particle model at the atomic scale. Every substance, whether an element, compound or mixture, is built from atoms. An element contains only one type of atom, and that atom is the smallest particle that can still be identified as that element. Atoms are not indivisible in reality, but for GCSE chemistry the key idea is that they are the fundamental building blocks of matter. For example, a piece of copper metal is made of copper atoms; a water molecule contains hydrogen and oxygen atoms. When you write a chemical symbol such as Fe, it represents one atom of iron. The statement also implies that atoms are conserved in chemical reactions, because they are the smallest parts that can exist and cannot be created or destroyed by ordinary chemical means. A strong answer earns marks for these points. State that all substances are composed of atoms. Define an atom as the smallest part of an element that can exist. Recognise that an element contains only one type of atom. Use the idea that atoms are the building blocks of all matter, including compounds and mixtures. A common slip: Confusing atoms with molecules: a molecule is a group of atoms bonded together, whereas an atom is a single particle. Instead, use the definition that an atom is the smallest part of an element. Exam tip: When asked to define an atom, include both 'smallest part' and 'of an element' to secure the mark.
Watch it explained
What is the one idea the video explains? Say it in a sentence.
Read the described scene instead
All substances are made of atoms. An atom is the smallest part of an element that can exist. This is the particle model at the atomic scale, and it applies to elements, compounds and mixtures. All substances, including compounds and mixtures, are built from atoms. An element contains only one type of atom. A water molecule contains hydrogen and oxygen atoms, showing atoms in a compound. So atoms are the fundamental building blocks. A chemical symbol such as Fe represents one atom of iron. A piece of copper metal is made of copper atoms. A water molecule contains hydrogen and oxygen atoms. So atoms are the building blocks of matter, and symbols can stand for a single atom of an element. Use the definition to distinguish atoms from larger particles. An atom is a single particle and the smallest part of an element. A molecule is a group of atoms bonded together. So one iron atom is written Fe, while a water molecule is a group of hydrogen and oxygen atoms. Atoms are not the same as molecules. A molecule is a group of atoms bonded together, while an atom is a single particle. In GCSE chemistry, atoms are treated as indivisible during chemical changes. They are rearranged, not broken apart, in chemical reactions. Also, atoms of different elements have different masses and properties. All substances are composed of atoms. An atom is the smallest part of an element that can exist. An element contains only one type of atom, and atoms are the building blocks of compounds and mixtures too. In chemical reactions, atoms are conserved: they are rearranged, not created or destroyed by ordinary chemical means.
Key words
Say what each word means before you turn the card.
Atom
Try answering aloud or in your head before turning the card.
Substance
Try answering aloud or in your head before turning the card.
Element
Try answering aloud or in your head before turning the card.
Molecule
Try answering aloud or in your head before turning the card.
See every definition
- Atom
- The smallest part of an element that can exist.
- Substance
- A material that can be an element, compound or mixture, and all substances are made of atoms.
- Element
- A substance that contains only one type of atom.
- Molecule
- A group of atoms bonded together.
There is more to this lesson
The full lesson goes on to check your understanding and help you earn the marks. Create a free account to carry on, with your progress saved.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge
Test your understanding of Atoms, elements and compounds: All substances are made of atoms. An atom is the smallest part of an element that can exist.
Active recall beats re-reading. Take an instant quiz now to test what you’ve learned and lock it into long-term memory.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge