Nuclear Science
Video Notes
Nuclear Science
Describe nucleus
Define an isotope and a radioactive isotope
Describe three forms of radioactive decay
Nuclear Science
Define half-life
Compare and contrast fission and fusion
reactions
Nuclear Science
Nucleus
Particles in nucleus are called nucleons
Consist of + charged protons and neutral
neutrons
Have almost 2000 times the mass of electrons
Are made up of quarks and leptons
There are over 200 particles that makeup the
nucleus
Nuclear Science
Atomic notation
The 13 is the atomic number = # of protons
= (z)
The 27 is the mass (a) = protons +
neutrons
Nuclear Science
has 13 protons and 14 neutrons, for a total
of 27 nucleons.
has 13 protons and 15 neutrons, for a total
of 28 nucleons.
These are examples of isotopes – atoms of
an element with the same protons and
different neutrons.
Nuclear Science
Isotopes are unstable – they break down
into other elements.
Neutron to proton ratio is usually 1 to 1
Larger nuclei need more neutrons than
protons
Nuclear Science
Forces acting on Nucleons
Strong forces
Forces of attraction between nucleons
Are independent of the charge of the nucleon
Are short range (only exist between nearest
neighbors)
Electrical force
Force of repulsion between like charged protons
Are long range
Nuclear Science
Isotopes are unstable – they break down
into other elements.
A radioactive isotope
Has an unstable nucleus
Spontaneously emits a particle and decays into
another element
This is also known as transmutation
Nuclear Science
Polonium and radium were discovered by
the Curies
Nuclear Science
Alpha, beta and gamma waves are energy waves
- not particles
Types of Radioactive Emission
Symbol
Composition
Stopped by
alpha
α
2p
2n
paper
beta
β
1e
aluminum
gamma
γ
energy
lead
Nuclear Science
Nuclear decay
The alpha decay above results in lead.
Nuclear Science
Beta decay
A neutron changes into a proton and an
electron
Nuclear Science
Half-life
The times it takes for half the mass of a
radioactive sample to decay
Ranges from a fraction of a second to billions
of years
Is not affected by external conditions