Download Chapter 25 – Types of Radiation 1. Alpha Radiation Alpha decay

Chapter 25 – Types of Radiation
1. Alpha Radiation
Alpha decay can be described by:
a. The nucleus of an atom splits into two parts
b. One of these parts (the alpha particle) goes zooming off.
c. The nucleus left behind has its atomic number reduced by 2 and its
mass number reduced by 4 (that is, by two protons and 2 neutrons).
Here is a typical alpha decay equation:
Which part is the alpha particle?
2. Beta Radiation
Beta decay can be described by:
a. A neutron inside the nucleus of an atom breaks down into a proton
b. It emits an electron which goes zooming off
c. The atomic number goes up by one and mass number remains
unchanged.
Here is a typical beta decay equation:
Which part is the beta particle?
*Beta particles have less charge than alpha particles and much less mass.
Consequently, beta particles are more penetrating!
3. Gamma Radiation
Gamma ray – a high energy photon emitted by a radioisotope; nuclei emit
gamma rays with either a beta particles or alpha particle.
Here is a typical gamma decay equation:
**Take note: Because the gamma ray has no mass or charge the emission of a
gamma ray does not alter the atomic or mass number of an atom. Gamma
rays are extremely penetrating and can be very dangerous.
Additional Nuclear Reactions
4. Positron Decay
Positron decay is the mirror image of beta decay and can be described as:
a. Something inside the nucleus breaks down causing a proton to
become a neutron.
b. It emits a positron which goes zooming off.
c. The atomic number goes down by one and the mass number remains
unchanged.
Here is a typical positron decay equation:
*Positron: a particle with the mass of an electron but a positive change.
5. Electron Capture
Electron capture can be described as:
a. An electron from the closest energy level falls into the nucleus,
which causes a proton to become a neutron.
b. The atomic number goes down by one and the mass number remains
unchanged.
Here is a typical electron capture equation:
*Note: This is the only nuclear equation where something enters the nucleus.
All of the three other decays have the nucleus splitting an emitting a
particle.