5.1.2
Atomic Structure
Atomic Model - Example
Atomic Model - Example
An atom has a small, positively-charged nucleus surrounded by orbiting negatively-charged electrons.
Size of Atoms vs Nucleus
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
Atoms
- If an atom was the size of Wembley Stadium, then...
Nucleus
Nucleus
- ...its nucleus would be the size of a garden pea!
The Charges of Sub-Atomic Particles
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.


Protons (+1)
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.


Electrons (-1)
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.


Neutrons (0)
Neutrons (0)
- Neutrons have a relative charge of 0 - they are neutral.
- Like protons, they are found in the nucleus.
1Space, Time & Motion
1.1Motion
1.2Forces
1.3Momentum & Impulse
2The Particulate Nature of Matter
2.1Thermal Concepts
3Wave Behaviour
3.1Oscillations
3.2Travelling Waves
3.3Wave Characteristics
3.4Wave Behaviour
3.5Standing Waves
3.6Simple Harmonic Motion
3.7Single Slit Diffraction
3.8Interference
3.9Doppler Effect
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
5Nuclear & Quantum Physics
5.1Discrete Energy & Radioactivity
5.2Nuclear Reactions
5.3The Interaction of Matter with Radiation
6Measurements
6.1Measurements & Errors
6.2Uncertainties & Errors
6.3Vectors & Scalars
Jump to other topics
1Space, Time & Motion
1.1Motion
1.2Forces
1.3Momentum & Impulse
2The Particulate Nature of Matter
2.1Thermal Concepts
3Wave Behaviour
3.1Oscillations
3.2Travelling Waves
3.3Wave Characteristics
3.4Wave Behaviour
3.5Standing Waves
3.6Simple Harmonic Motion
3.7Single Slit Diffraction
3.8Interference
3.9Doppler Effect
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
5Nuclear & Quantum Physics
5.1Discrete Energy & Radioactivity
5.2Nuclear Reactions
5.3The Interaction of Matter with Radiation
6Measurements
6.1Measurements & Errors
6.2Uncertainties & Errors
6.3Vectors & Scalars
Unlock your full potential with Seneca Premium
Unlimited access to 10,000+ open-ended exam questions
Mini-mock exams based on your study history
Unlock 800+ premium courses & e-books