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Year 10
Edexcel
Foundation

Atomic structure (negligible electron mass)

I can describe the physical characteristics of atoms, protons, neutrons and electrons.

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New
New
Year 10
Edexcel
Foundation

Atomic structure (negligible electron mass)

I can describe the physical characteristics of atoms, protons, neutrons and electrons.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. Electrons have a relative charge of -1 and roughly a relative atomic mass of 1/1835 (negligible).
  2. Protons are found in the atomic nucleus, have a relative electric charge of +1, and a relative mass of 1.
  3. Neutrons are found in the atomic nucleus, have no electric charge, and a relative mass of 1.
  4. An atom has no electric charge as it contains equal numbers of protons and electrons to balance the charge.
  5. The atom has a nucleus surrounded by electrons, with the nuclear radius much smaller than that of the atom.

Common misconception

Students often struggle with the idea of how small an atom actually is. In contrast, how small the nucleus is, relative to the size of the atom.

The use of units and numbers to show the difference in size, e.g. the atom is approximately 10, 000 times larger than the nucleus. The radius of the atom is 0.1nm and the nucleus very small compared to that of the atom.

Keywords

  • Electron - An electron is a subatomic particle with a negative charge and a very small relative mass of 1/1835 (negligible).

  • Proton - A proton is a subatomic particle with a positive charge and a relative atomic mass of 1.

  • Neutron - A neutron is a subatomic particle with no charge and a relative atomic mass of 1.

  • Nucleus - A nucleus is found in the centre of an atom. It consists of protons and neutrons. It is significantly smaller in size than the atom.

  • Subatomic - Anything that is smaller than an atom. There are three subatomic particles called electrons, protons and neutrons.

Real analogies such as the marble (nucleus) vs football stadium (atom) with images help to show the size difference. Facts of how many atoms a human is made up of, or how many atoms are in a cell (often mistakenly thought of as the size of an atom) really help.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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Starter quiz

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6 Questions

Q1.
Which statement is true about elements?
They are composed of multiple types of atoms.
They can be broken down into simpler substances by chemical means.
Correct answer: They are the simplest form of matter that can exist under normal conditions.
They are all metals.
Q2.
What determines the identity of an element?
The number of molecules it has
Correct answer: The type of atoms it is made up of
Its physical state
Its colour
Q3.
In a chemical reaction, atoms...
change into different elements.
are destroyed.
are created.
Correct answer: rearrange to form new substances.
Q4.
An element is a substance made up of only one kind of ...
Correct Answer: atom
Q5.
John Dalton's theory proposed that are indivisible.
Correct Answer: atoms, atom
Q6.
The is a list of all known elements, ordered based on their properties.
Correct Answer: periodic table

Exit quiz

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6 Questions

Q1.
Where is the nucleus located in an atom?
Outside the electron shells
Correct answer: In the centre
In the electron
It varies
Q2.
Match the subatomic particles with their relative charges:
Correct Answer:electron,-1

-1

Correct Answer:proton,+1

+1

Correct Answer:neutron,0

0

Q3.
The relative mass of a neutron is (compared to protons).
Correct Answer: 1, one
Q4.
True or false? Atoms are overall neutral. (Select true or false and a justification.)
Correct answer: True
False
they have the same numbers of protons and neutrons
Correct answer: they have the same numbers of protons and electrons
they have the same numbers of electrons and neutrons
Q5.
Which of the following are correct ways of describing the relative mass of electrons (compared to protons)?
Correct answer: 1/1835
Correct answer: negligible
0
-1
0.1835
Q6.
The radius of an atom's is at least 10 000 times smaller in comparison to the radius of the whole atom.
Correct Answer: nucleus