Ch. 14 Natural Radioactivity

Natural Radioactivity, nuclear reactions, radiation measurements, half life, med app, nuclear fission and fusion

radioactivity comes from…

unstable nuclei

unstable nuclei are (1)…

found in C, H, and elements w/ atomic #’s 20+

Unstable nuclei are… (2)

defined as nuclei which nuclear forces can’t offset the repulsions between protons

Unstable nuclei are… (3)

radioactive, emitting small particles of energy called radiation to become more stable

Radiation may take form of…

alpha, beta particles, positrons, or pure energy like gamma rays

radioisotopes are… (1)

isotopes of an element that emits radiation

radioisotopes are… (2)

one or more isotopes of an element

radioisotopes are… (2)

including the mass number in its name

atomic symbol iodine-131 is a radioisotope with…

mass number 131 and atomic number 53

alpha particles are identical to…

a helium nucleus

Beta particles

High energy electrons

Positrons

Gamma rays

Pure energy

radioactive decay

nucleus breaks down by emitting radiation

alpha decay

form a new nucleus with a mass number decreased by 4 and atomic number decreased by 2

beta decay

mass number of new nucleus remains, atomic number increases by 1

positron emission

proton converted to neutron and positron, mass remains but atomic number decreases by 1

gamma radiation

energy emitted from unstable nucleus, numbers remain the same

radioactive isotopes are produced…

when stable nucleus convert to radioactive nucleus by bombarding it with small particles aka transmutation

Geiger counter

detects alpha, beta, and gamma rays, uses ions produced by radiation to create an electrical current

rem (radiation equivalent in humans)

measures alpha particles in the body, high-energy radiation, and gamma rays

alpha particles, if entered the body…

cause extensive damage in tissue

high-energy radiation causes…

more damage than alpha particle, includes beta particles, high-energy protons, and neutrons that travel into tissue

gamma rays cause…

damage bc they travel a long way through body tissue

biological damage (rem) =

absorbed dose (rad) x factor

activity

curie (Ci), becquerel (Bq)

Half-life

radioisotope’s time for radiation level to decay to one-half of OG value

decay curve

illustrates amount of time thats needed for one half of substance to be converted into a different element

nuclear fission

a large nucleus bombarded with a neutron making an unstable isotope

atomic energy

unstable isotope splits and release large amounts of energy

fusion reactions

occur at extremely high temps, combining small nuclei into large ones, release large amounts of energy