Slide 1
NUCLEAR EQUATIONS
Alpha DecayAn alpha particle looks like a helium atom (42He)mass
reduces by 4 ,the atomic # reduces by 2Examples:23892 U 20984
Po
23490 Th + 42He20582 Pb + 42He
2Beta Decay A beta particle is written 0-1 emass remains the
same & the atomic # increases by oneExamples:21482 Pb21884
Po
21483 Bi + 0-1 e21885 At + 0-1 e
3Gamma decayA gamma ray is a penetrating ray of energy emitted
by an unstable nucleusGamma rays are energy waves that travel
through space at the speed of light
4
Gamma decayatomic # and mass remain the same, but the energy of
nucleus decreasesGamma rays can be stopped by several centimeters
of lead or by several meters of concrete
5Background radiationis nuclear radiation that occurs naturally
in the environment (levels are low enough to be safe)Radioisotopes
in the air, water, rocks, plants, & animals all contribute
6
Background RadiationCosmic rays (streams of charged particles)
from outer space that collide with the Earths atmosphere also
contributeWhen nuclear radiation exceeds background levels, cells
in your body can mutate
7Detecting Radiation Devices used to detect radiation include
Geiger counters & film badges
8RATES OF NUCLEAR DECAYA half-life is the time required for one
half of a sample of radioisotope to decayUnlike chemical reactions,
nuclear decay rates are constant regardless of temperature,
pressure or surface areaHow much of the original sample will remain
after 5 half-lives?
9RATES OF NUCLEAR DECAYTransmutation is the conversion of atoms
of one element to atoms of anotherTransuranium elements are
elements with atomic numbers higher than 92A quark is a subatomic
particle theorized to be among the basic units of matter10
