Radiochemistry Flashcards
What are isotopes?
Atoms that have the same number of protons but different number of neutrons in their nuclei.
What are radioisotopes?
Isotopes that are radioactive. They have unstable atomic nuclei and lose energy by emitting radiation.
What radioisotopes emit radiation as alpha particles?
Isotopes with an atomic number of 60 or higher.
What radioisotopes emit radiation as beta particles?
Isotopes with excess neutrons.
What is decay often accompanied by?
The emission of electromagnetic radiation such as gamma or x-ray.
What is the difference between an alpha and beta particle?
An alpha particle is a helium nucleus (two protons and two neutrons) whereas a beta particle is a fast moving electron.
What are the key properties of alpha particles?
Slow-moving, small range in air (3cm), no external hazard but contamination can be very serious.
What are the key features of beta particles?
A variable energy, a 1m range in air, have an external and contamination hazard.
What are they key features of gamma particles and x-ray particles?
A long rang and have an external hazard.
What is a half life?
The time taken for half a radioactive material to become stable.
What is the inverse square law?
The idea that the energy of radiation decreases in proportion to the square of the distance from its source.
What regulations surround the use of radioactive substances?
The radioactive substances act and the ionising radiations regulations.
What safety precautions must be taken?
Sufficient training (knowledge, planning and preparation), shielding, distance, reduced exposture time and always working together.
What are the major isotopes used in the life sciences?
Phosphorus-32, sulfur-35, tritium (3H0 and iodine-125.
What is the half life of phosphorus 32?
14.3 days.
What is the range in air of phosphorus 32?
790cm.
What is sufficient shielding for phosphorus 32 and sulfur 35?
1cm perspex.
What are some of the uses of phosphorus 32?
Labelling nucleic acids such as in DNA fingerprinting.
What is the half life of sulfur-35?
87.4 days.
What is the range of sulfur 35?
26cm in air.
What are the uses of sulfur 35?
Labelling proteins and DNA sequencing.
What is the half life of tritium?
12.4 years
What is the radiation of tritium, phosphorus 32 and sulfur 35?
Beta.
What is the range of tritium?
6mm in air.
