Radionuclides in the Environment Flashcards
Describe the term “radioisotope/radionuclide”
A radioisotope/radionuclide is an atom that has excess nuclear energy, making it unstable and radioactive.
Describe the term “decay series”
Decay series is a series of decay in which radioactive element is decomposed in different elements until it produces one stable element.
Describe the alpha decay series
a radioactive process in which an alpha particle is emitted from the nucleus of an atom, decreasing its atomic number by two.
Describe the beta decay series
in beta decay, the nucleus converts a neutron into a proton and a beta particle, which is an electron. After transmutation, the daughter particle has one more proton and one fewer neutron so the atomic number increases by one, and the mass number stays the same.
Describe the gamma decay series
type of radioactivity in which an unstable atomic nucleus dissipates energy by gamma emission, producing gamma rays.
Describe the term “half-life”
the time taken for the radioactivity of a specified isotope to fall to half its original value.
Describe the term “radioactivity”
the spontaneous emission of high energy particles / electromagnetic rays when a nucleus disintegrates
Who was first to discover radioactivity?
Henri Becquerel - he exposed potassium uranyl sulfate to sunlight and then placed it on photographic plates wrapped in black paper, believing that the uranium absorbed the sun’s energy and then emitted it as x-rays. Upon developing the photographic paper, the images were strong and clear, despite the low levels of sun light when they were originally exposed, proving that the uranium emitted radiation without an external source of energy such as the sun. Becquerel had discovered radioactivity.
Which types of rocks contain natural occurring radiation?
Igneous rocks
What is the atomic number of an atom?
(Z) the number of protons found in the nucleus
What is the mass number of an atom?
the total number of protons and neutrons in an atomic nucleus
Define the term “isotope”
isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons
Define the term “relative atomic mass”
RAM is the weighted mean average of all the known isotopes
Define the term “linear energy transfer”
It describes the action of radiation into matter. linear energy transfer (LET) is the amount of energy that an ionizing particle transfers to the receiving material (traversed per unit distance)
What does the equation, 𝐴𝑡 = 𝐴0𝑒−𝜆𝑡, represent?
Radioactive decay rate
A - activity
𝜆 - decay constant (units of time -1)
e - is 2.718 (ex on calculator)
t - is time
What does the equation, t½ = ln2 / λ represent?
Half life
How does radiation damage cells?
1 - Produce free radicals, ~70% cell is water (peroxide, OH. O2-)
2 - Break chemical bonds directly or by high energy electrons.
3 - Produce new chemical bonds and cross-linkage between macromolecules.
4 - Damage replicating molecules that regulate
vital cell processes (e.g. DNA, RNA, proteins).
(Biggest problem)
What does the term “acute” mean, with reference to radioactive exposure?
Short, high intensity exposure
What does the term “chronic” mean, with reference to radioactive exposure?
long term
What does the term “internal” mean, with reference to radioactive exposure?
via consumption, inhalation or injection of a radionuclide
What does the term “external” mean, with reference to radioactive exposure?
- in the surrounding environment
- exposure depends on the ability of radioactive emissions to enter you
When referring to internal exposure, which of Gamma, Alpha and Beta emissions are released directly into the body?
Gamma, Alpha and Beta
When referring to internal exposure, which of Gamma, Alpha and Beta has the highest linear energy transfer?
Alpha, it deposits the most energy in a concentrated zone.
When referring to internal exposure, which of Gamma, Alpha and Beta interacts to the least extent?
Gamma
Elements with an atomic number greater than what, undergo radioactive decay due to instability?
83
