Particle Physics
Constituents of the atom (3.2.1.1)
● An atom is made up of a nucleus containing protons and neutrons and shells
containing electrons in an orbit around the nucleus
This data is provided on the data sheet.
Relative Charge in SI Relative mass Mass in SI
charge units (C) units (kg)
Neutron 0 0 1 1.67x10^-27
Proton 1 1.6x10^-19 1 1.67x10^-27
Electron -1 -1.6x10^-19 0.0005 9.11x10^-31
● Specific charge is the charge per unit of mass. It is calculated by charge (in
Coulombs)/mass (in kilograms). This is not given in the data sheet.
● The atomic number is the number of protons in a nucleus
● The nucleon number is the number of both protons and neutrons in the nucleus
● The nucleon number is the larger number presented with the elemental symbol and
the atomic number is the lower number
● Isotopes are atoms of the same element but with a different mass number. They
have the same number of protons and hence the same atomic number.
Stable and unstable nuclei (3.2.1.2)
● The strong nuclear force holds the nucleons of an atom together
● It is repulsive up to 0.5fm and attractive between 0.5 and 3fm
● It is very short range so is negligible after 3fm.
Unstable nuclei can undergo alpha or beta decay.
Here is the equation for alpha decay.
And here is the equation for Beta minus decay
Here an electron antineutrino is emitted to conserve lepton number
Constituents of the atom (3.2.1.1)
● An atom is made up of a nucleus containing protons and neutrons and shells
containing electrons in an orbit around the nucleus
This data is provided on the data sheet.
Relative Charge in SI Relative mass Mass in SI
charge units (C) units (kg)
Neutron 0 0 1 1.67x10^-27
Proton 1 1.6x10^-19 1 1.67x10^-27
Electron -1 -1.6x10^-19 0.0005 9.11x10^-31
● Specific charge is the charge per unit of mass. It is calculated by charge (in
Coulombs)/mass (in kilograms). This is not given in the data sheet.
● The atomic number is the number of protons in a nucleus
● The nucleon number is the number of both protons and neutrons in the nucleus
● The nucleon number is the larger number presented with the elemental symbol and
the atomic number is the lower number
● Isotopes are atoms of the same element but with a different mass number. They
have the same number of protons and hence the same atomic number.
Stable and unstable nuclei (3.2.1.2)
● The strong nuclear force holds the nucleons of an atom together
● It is repulsive up to 0.5fm and attractive between 0.5 and 3fm
● It is very short range so is negligible after 3fm.
Unstable nuclei can undergo alpha or beta decay.
Here is the equation for alpha decay.
And here is the equation for Beta minus decay
Here an electron antineutrino is emitted to conserve lepton number
