What is radioactivity?
· The spontaneous emission of energy from unstable atoms
· Atoms – Neutrons:Protons (ratio) is not ideal
· Nucleus approaches a more stable neutron to proton ratio
· Radioactive decay releases different types of energetic emissions
o Fission
The three most common types of radioactive emissions
· Alpha particles
o Made up of two protons and two neutrons
o Often referred to as a helium nucleus
o Positively charged nuclear particle
o Emitted spontaneously in some types of radioactive decay
o Produced when Helium atoms are completely ionised
o
· Beta particles
o Form of ionizing radiation
o Closely related to other types of radiation
o High-speed electron that has been released from a degenerative radioactive nucleus
o Low mass and medium-energy
o One of the least-damaging types of radiation
o Pose a large health risk – break chemical and create ions, lead to tissue damage
o Not radioactive
· Gamma rays
· Composed of electromagnetic
· Very penetrating
· Most useful type of radiation for medical purposes,
o Also most dangerous because of its ability to penetrate large thicknesses of material
· Among all electromagnetic waves, gamma rays have
o Shortest wavelengths
o Highest frequencies
o Highest energies
· Most energetic form of light
· Produced by the hottest regions of the universe
Interesting facts about radioactivity
· Radioactive elements break down (decay) to form lighter atoms
o Energy released is made up of small, fast-moving particles and high-energy waves(invisible)
o Elements with naturally occurring radioactive forms
§ Carbon
§ Bismuth
§ Radon
§ Strontium
· Random process that happens naturally as the isotopes in particular elements decay
· Isotopes continue to break down over time
· The length of time that is taken for half of the nuclei in an element to decay is called its 'half-life'(refer to the topic above)
o Can be very short (milliseconds to hours) or very long (hundreds of thousands of years).
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