AQA · GCSE · Combined Science

Course version: 8464 · Version from Sept 2018

Atoms, elements and compounds: Atoms of each element are represented by a chemical symbol, eg O represents an atom of oxygen, Na represents an atom of sodium.

Q: How do I revise Atoms, elements and compounds: Atoms of each element are represented by a chemical symbol, eg O represents an atom of oxygen, Na represents an atom of sodium. for GCSE?

Read the notes on Atoms, elements and compounds: Atoms of each element are represented by a chemical symbol, eg O represents an atom of oxygen, Na represents an atom of sodium., then test yourself without looking. Answering questions and checking what you missed builds recall faster than re-reading.

Q: Is this Atoms, elements and compounds: Atoms of each element are represented by a chemical symbol, eg O represents an atom of oxygen, Na represents an atom of sodium. guide aligned to the AQA specification?

Yes. This guide is linked to the Atoms, elements and compounds: Atoms of each element are represented by a chemical symbol, eg O represents an atom of oxygen, Na represents an atom of sodium. topic in the AQA GCSE specification.

Chemists use chemical symbols as a universal shorthand for elements.

2 key terms

Study notes

From the checked teaching notes for this specification point.

The idea

Chemists use chemical symbols as a universal shorthand for elements. Each element has its own symbol, so O means one atom of oxygen and Na means one atom of sodium. Symbols are one or two letters: the first letter is always a capital, and a second letter, if present, is always lower case, as in Na, Mg and Cl. Many symbols come from the English name, but some come from the Latin name, which is why sodium is Na (from natrium), potassium is K (from kalium) and iron is Fe (from ferrum). A symbol can represent one atom of the element, and in a formula it shows how many atoms of that element are present, for example H₂O contains two hydrogen atoms and one oxygen atom. Learning symbols allows scientists worldwide to read and write formulae consistently.

What earns the marks

States that each element has its own chemical symbol.
Interprets a symbol such as O or Na as representing one atom of that element.
Applies the capital-then-lower-case rule when writing symbols, for example Na and Cl.
Recognises that some symbols come from Latin names, such as Na for sodium and Fe for iron.
Uses symbols within a formula to show the number of atoms of each element present.

Common mistakes and how to put them right

Writing both letters as capitals, such as NA.
Put it right: Correct this to Na, because only the first letter is a capital.
Treating a symbol as a word abbreviation only.
Put it right by noting that Na represents one atom of sodium, not the word 'sodium'.
Reading H₂O as one hydrogen atom.
Put it right by using the subscript to show two hydrogen atoms and one oxygen atom.

Exam tips

Learn the symbols for common elements, including those with Latin origins such as Na, K and Fe, because they are frequently used in formulae.
When naming an element from its symbol, check the capital and lower-case letters carefully before answering.
Practise counting atoms in formulae such as CO₂ and CaCO₃ so you can link symbols to numbers of atoms.

Try the lesson

The start of the Atoms, elements and compounds: Atoms of each element are represented by a chemical symbol, eg O represents an atom of oxygen, Na represents an atom of sodium. lesson, made from checked teaching notes for this specification point.

Have a go first

The chemical symbol for sodium is Na and the chemical symbol for chlorine is Cl. Which statement correctly describes what these symbols represent?

Tip: press 1 to 4 to choose

See it

A top-down flowchart. The top node reads 'Each element has its own chemical symbol' and branches to five nodes. The first branch reads 'O = one atom of oxygen'. The second reads 'Na = one atom of sodium'. The third reads 'First letter always capital', which leads down to 'Second letter, if present, always lower case', which leads to 'Na, Mg, Cl'. The fourth branch reads 'Some symbols come from Latin names' and splits into three: 'Na from natrium', 'K from kalium' and 'Fe from ferrum'. The fifth branch reads 'In a formula a symbol shows how many atoms are present', which leads to 'H₂O contains two hydrogen atoms and one oxygen atom'. — It shows that each element has its own chemical symbol, the capital-then-lower-case rule, Latin-name origins and how symbols show numbers of atoms in a formula.

Key words

Say what each word means before you turn the card.

Chemical symbol

Try answering aloud or in your head before turning the card.

Formula

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See every definition

Chemical symbol: A representation of an atom of each element, such as O for an atom of oxygen or Na for an atom of sodium.
Formula: Shows how many atoms of each element are present, for example H₂O contains two hydrogen atoms and one oxygen atom.

Label the diagram

Some boxes have lost their names. Pick the right name for each number.

The diagram again, with 3 boxes numbered instead of named. A top-down flowchart. The top node reads 'Each element has its own chemical symbol' and branches to five nodes. The first branch reads 'O = one atom of oxygen'. The second reads 'Na = one atom of sodium'. The third reads 'First letter always capital', which leads down to 'Second letter, if present, always lower case', which leads to 'Na, Mg, Cl'. The fourth branch reads 'Some symbols come from Latin names' and splits into three: 'Na from natrium', 'K from kalium' and 'Fe from ferrum'. The fifth branch reads 'In a formula a symbol shows how many atoms are present', which leads to 'H₂O contains two hydrogen atoms and one oxygen atom'.

1Box 1
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