New
New
Year 10
Edexcel
Higher

# Atomic structure (negligible electron mass)

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

New
New
Year 10
Edexcel
Higher

# Atomic structure (negligible electron mass)

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

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## 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.

### 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).

## Starter quiz

### 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
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 ...
Q5.
John Dalton's theory proposed that are indivisible.
Q6.
The is a list of all known elements, ordered based on their properties.

## Exit quiz

### 6 Questions

Q1.
Where is the nucleus located in an atom?
Outside the electron shells
In the electron
It varies
Q2.
Match the subatomic particles with their relative charges:

-1

+1

0

Q3.
The relative mass of a neutron is (compared to protons).
Q4.
True or false? Atoms are overall neutral. (Select true or false and a justification.)
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)?