2. NUCLEAR EQUATIONS

3. Alpha Decay An alpha particle looks like a helium atom ( 4 2 He) massatomicmass reduces by 4,the atomic # reduces by 2 Examples: 238 92 238 92 U  209 84 209 84 Po  234 90 4 2 234 90 Th + 4 2 He 205 82 4 2 205 82 Pb + 4 2 He

4. Beta Decay A beta particle is written 0 -1 e mass remains the same & the atomic # increases by one Examples: 214 82 Pb  218 84 Po  214 83 Bi + 0 -1 e 218 85 At + 0 -1 e

5. Gamma decay A gamma ray is a penetrating ray of energy emitted by an unstable nucleus Gamma rays are energy waves that travel through space at the speed of light

6. atomic # and mass remain the same, but the energy of nucleus decreases Gamma rays can be stopped by several centimeters of lead or by several meters of concrete

7. Background radiation is nuclear radiation that occurs naturally in the environment (levels are low enough to be safe) –R–Radioisotopes in the air, water, rocks, plants, & animals all contribute

8. Background Radiation –Cosmic rays (streams of charged particles) from outer space that collide with the Earth’s atmosphere also contribute –When nuclear radiation exceeds background levels, cells in your body can mutate

9. Detecting Radiation Devices used to detect radiation include Geiger counters & film badges

10. RATES OF NUCLEAR DECAY A half-life is the time required for one half of a sample of radioisotope to decay –Unlike chemical reactions, nuclear decay rates are constant regardless of temperature, pressure or surface area –How much of the original sample will remain after 5 half-lives?

11. RATES OF NUCLEAR DECAY Transmutation is the conversion of atoms of one element to atoms of another Transuranium elements are elements with atomic numbers higher than 92 A quark is a subatomic particle theorized to be among the basic units of matter