Nuclear Chemistry
•Marie Curie discoveredthat there wassomething going on insidethe Uranium atom thatcreated the rays, shenamed this effect“radioactivity”
Nuclear SymbolsNuclear Symbols
Element symbol
Mass number
(p+ + no)
Atomic number
(number of p+)
RadioactiveDecay
Radioactivity
◦when a nucleus spontaneously decomposes, forming adifferent nucleus and producing one or more particles.
Nuclear Equation
◦Both the atomic number and the mass number must beconserved.
◦That is the sums of both on each side must be equal.
Radioactive Particles
Particle Type
Symbol
Mass
PenetratingPower
Alpha Particle
4
Low Blocked bypaper or clothing
Beta Particle
0
Moderate Blockedby metal foils
Gamma Ray
0
High Incompleteshielding by lead andconcrete.
Types of Radioactive Decay
Type
Definition
End Result
Alpha-particleProduction
Decay of the nucleus of a large atomthat results in the formation of analpha particle
Atomic mass reduced by 4 andatomic number is reduced by 2
Beta-particleProduction
The net effect of beta-particleproduction is to change a neutron toa proton. Releases a beta-particle.
No change in mass number, butan increase in one of the atomicnumber
PositronProduction
Positron has the same mass as anelectron, but opposite charge. Notcommon.
No change in mass. But adecrease in one of the atomicnumber.
ElectronCapture
A process in which one of the inner-orbital electrons is captured by thenucleus
Atomic number decreases byone, but the mass remains thesame.
Gamma Rays
Gamma rays are photons ofelectromagnetic radiation with highfrequency and energy.
Gamma rays are given off during othertypes of radioactive decay.
Half-life
The time required forhalf of the originalsample of nuclei todecay.
Half-life ConceptHalf-life Concept
Decay Series
A decay series will
occur until a stable
nuclide is formed.
Nuclear Fission
The process of splitting an atom.
Releases an enormous amount of energy.
◦1 mol of uranium-238 can produce about 26 million timesas much energy as 1 mol of methane.
Nuclear Fusion
The process of combiningtwo light nuclei.
◦Produces more
energy than fission.
Radiation may be absorbed by the medium it passesthrough.
Radiation can kill living cells or change the nature ofliving cells.
Effects of Radiation onLiving Organisms
Making Use of Radioactivity
Humans have the ability to harness andmanipulate radioactivity for:
◦National defense and weaponry
◦Medical diagnosis and treatments
◦Energy production
◦Radioactive Dating
Radiation Detection
Approximate amounts ofradiation can be detected bythe following devices:
•Film badge
•Geiger-Muller counter
•Scintillation counter
Radiation Detection
The film badge is worn on a lapel, thewrist, or finger, and detects theapproximate accumulated dose ofradiation over time.
People who work with radiation, such as x-raytechnicians, will wear such a device.
Radiation Detection
The Geiger-Muller counter detects theapproximate radiation present at any given timeby counting electric pulses carried by gasionized by radiation.
The Geiger-Muller counter would be used to detectan approximate radiation dose that a person hasbeen exposed to, such as when the Fukushimanuclear power plant leaked radiation.
The scintillation countercan detect ionizingradiation. Somesubstances absorb. e
A scintillation counterwould be used in bordersecurity, homeland security,and nuclear plant safety,among other things.
Radiation Detection
The scintillation countercan detect ionizingradiation. Somesubstances absorbionizing radiation and emitvisible light, or scintillate.