Types of Radiation
1. Alpha radiation is radiation that was deflected toward the negatively charged plate alpha radiation.
· Made up of 2 alpha (a) particles
Ø Each alpha particle contains 2 protons and 2 neutrons
Ø Has a 2+ charge
Ø Has a mass of 4 amu
· alpha reaction formula: See in class
2. Beta radiation is radiation deflected toward the positively charged plate beta radiation.
· Consist of fast moving electrons known as beta (b) particles.
Ø Each beta particle contains an electron with a -1 charge.
§ Beta reaction formula: See in class
3. Gamma radiation is the third common type and uses gamma rays.
· Gamma rays (g) are high-energy radiation that possesses no mass.
Ø Because they possess no electrical charge, gamma rays are not deflected by electric or magnetic fields.
Ø Usually will accompany alpha and beta radiation.
Ø Accounts for most of the energy lost during the radioactive decay process.
§ Since gamma rays have no mass, the emission of gamma rays by themselves can't result in the formation of a new atom.
Half-Life Formula
1.) How to determine the number of years for so many half-lives: find reference value and multiple it by the number of half-lives. Example: There are 5730 years in one half-life of C-14. How many years are in 4 half-lives? 5730 x 4= 22920 years
2.) Determine the Amount remaining:
a.) Amount Remaining= Original Amount of parent ÷ 2n n=half-life Example: Four half-lives of C-14 is 22920 years. The Initial amount is 6g of C-14. How much is lost in 4 half-lives. 6g ÷ 24 6g ÷ 16= .375 g left. How much is lost 6-.375=5.625 g
b.) How many half-lives is there in Potassium -40 (one half-life of 1250000000 years) when an initial sample had 15g and the amount remaining is 3.75g? 15 x1/2=7.5 7.5x1/2=3.75 2 half-lives
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