Upload
lawrence-stone
View
216
Download
1
Embed Size (px)
Citation preview
Nuclear Chemistry
Radioactivity:
Definition: occurs when the nucleus of an unstable atom emits ionizing radiation
Radiation- the movement of energy by particles or wavesElectromagnetic radiation
Non-ionizing Radiation- low energy; usually not harmful
Ionizing Radiation- carry enough energy to “ionize” atoms
Elements after atomic number 83 are radioactive
Isotope –
Radioisotope-
Nuclear Reactions Involve a change in the atom’s
nucleus (protons and neutrons)
Types:FissionFusion
Types of RadiationAlpha α (Alpha Decay)
Alpha particle = 2p+ and 2n0
U Th + He + 2 + ϒ
Alpha particle is a He nucleusϒ accounts for energy lost during reactionIn the reaction, we must conserve p+ and n0
Don’t penetrate too far, but can cause skin problemsSources have a long half-life (around for a long time)Discovered by Rutherford and his students (Geiger)
Types of RadiationBeta ϐ (Beta Decay)
Beta particle: fast moving electron (-1 charge) ϐ or eFormed when a neutron is split into a proton and a ϐ
particle (electron) n p + ϐ + ϒ
There is no change in the mass #, only in atomic #Atomic # changes because the e- emitted during ϐ rxn (ϐ
decay) has been removed from a neutron (charge of 0) leaving behind a proton
Rb Sr + e-
Damaging to skin because they can travel through a few inches of tissue
Types of RadiationGamma Rays
Gamma Rays: high energy radiation (electromagnetic) that is massless
No electrical chargeOften accompany α and ϐ reactionsHarmful- can deeply penetrate skin
http://www.bcm.edu/bodycomplab/Radprimer/radpenetration.htm
Electromagnetic Spectrum
Practice Equations:
Radiation ExposureAccumulated Doses
Measured in units called rem: measures doses of radiation while accounting for energy of radiation, type of living tissue absorbing radiation and time of exposure.
Background radiation- Where does this it come from?
Radiation ExposureHow do we detect radiation?
Geiger CounterTube filled with gas that absorbs radiation and
becomes ionized charge current measure the amount of radiation