5.1.2

Atomic Structure

Test yourself

Atomic Model - Example

An atom has a small, positively-charged nucleus surrounded by orbiting negatively-charged electrons.

Size of Atoms vs Nucleus

Atoms have a radius of about 1 × 10-10 metres. However, the nucleus of an atom is even smaller.

Atoms

  • If an atom was the size of Wembley Stadium, then...

Nucleus

  • ...its nucleus would be the size of a garden pea!

The Charges of Sub-Atomic Particles

The 3 different sub-atomic particles (protons, neutrons and electrons) have different relative charges. Atoms have no overall charge (are neutral). In an atom, these charges all cancel each other out.

Illustrative background for Protons (+1)Illustrative background for Protons (+1) ?? "content

Protons (+1)

  • Protons have a relative charge of +1.
  • They are found in the nucleus.
  • An element’s atomic number is the number of protons it possesses.
    • All atoms of the same element have the same number of protons.
Illustrative background for Electrons (-1)Illustrative background for Electrons (-1) ?? "content

Electrons (-1)

  • Electrons have a relative charge of -1.
  • They are found in fixed orbits around the nucleus.
  • In any atom, the total number of negative electrons equals the number of positive protons, meaning atoms have no overall electric charge.
Illustrative background for Neutrons (0)Illustrative background for Neutrons (0) ?? "content

Neutrons (0)

  • Neutrons have a relative charge of 0 - they are neutral.
  • Like protons, they are found in the nucleus.

Jump to other topics

1Space, Time & Motion

2The Particulate Nature of Matter

3Wave Behaviour

4Fields

4.1Circular Motion

4.2Newton's Law of Gravitation

4.3Fields

4.4Fields at Work

4.5Electric Fields

4.6Magnetic Effect of Electric Currents

4.7Heating Effect of Currents

4.8Electromagnetic Induction

4.9Power Generation & Transmission

4.10Capacitance

5Nuclear & Quantum Physics

6Measurements

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