Nuclear Notation
The symbol for an atom is often written in the form:-
Nuclear Decay
From National 5 Physics, you know that three types of radioactivity may be emitted from atomic nuclei during radioactive decay - alpha particles, beta particles and gamma rays.
Alpha Decay
Alpha decay takes place when an alpha particle (consisting of 2 protons plus 2 neutrons) is ejected from an atom's nucleus.
An alpha particle is represented by the symbol:-
A different element is also created as a result:-
The mass number of the new (daughter) atom is four less than the original (parent). The atomic number is two less than the original. Mass number and atomic number must be conserved.
Beta Decay
Beta decay takes place when a neutron in the nucleus decays into a proton and an electron. The proton stays in the nucleus (so the atomic number increases by 1) while the Electron is ejected from the atom's nucleus as a beta particle.
A Beta particle is represented by the symbol:
A different element is also created as a result:-
The mass number of the new (daughter) atom is the same as the original (parent). The atomic number is increased by 1. Mass number and atomic number must be conserved.
Gamma Decay
Gamma rays are photons of electromagnetic Energy - They are not particles. When Gamma rays are ejected from an atom's nucleus, this does not change the mass number or atomic number of the atom. It does however change the Energy state of the nucleus.
