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Subatomic Particles: The Neutron
The observer.
Covered in this Lesson
• This lesson will explain that neutrons are
particles in the nucleus that have no
charge and a mass of one amu.
Discovery of the neutron
• Ernest Rutherford suggested the idea of a
neutron in 1920.
• James Chadwick in 1932, through
experimentation, suggested a particle with a
mass of a proton and a neutral charge. We call
this particle the neutron.
The neutron
• Neutrons are in the nucleus which has the
vast majority of the mass in an atom.
• A neutron’s mass is about the same as a
proton
• The mass is about 2000 time that of an
electron.
• The volume of the nucleus is about 100,00
time smaller than the whole atom.
properties
• The neutron has
- no charge.
- mass of about 1 atomic mass unit (amu)
that is equivalent to about 1.7X10-27 kg
Model of the Atom
electron cloud
Nucleus – the
green balls
are the
neutrons
Diagram clipart.dk.uk