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Nuclear Radiation. Half-Life. What is Radiation?. Penetrating rays and particles emitted by a radioactive source Result of a nuclear reaction! Involves the changing of the atoms nuclei. Radioisotopes. Isotopes Elements with the same # of protons & electrons, but a different # of neutrons!
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Nuclear Radiation Half-Life
What is Radiation? • Penetrating rays and particles emitted by a radioactive source • Result of a nuclear reaction! • Involves the changing of the atoms nuclei
Radioisotopes • Isotopes • Elements with the same # of protons & electrons, but a different # of neutrons! • Radioisotopes • Unstable isotopes • In nuclear rxns their nuclei undergo changes to become stable
Chemical vs. Nuclear rxns Chemical Rxns Nuclear Rxns Nuclei are changed to become stable Involve large amounts of energy being emitted Not affected by anything & cannot be stopped • Involve the transfer or sharing of e- • Nuclei are unchanged • Affected by ∆ in temp, pressure & catalyst
Nuclear Stability • Depends on the ratio of neutrons to protons in the nucleus & the overall size of the nucleus • Too many or too few neutrons makes the nucleus unstable • Unstable nucleus releases energy by emitting radiation during radioactive decay!
Types of Radiation • 3 main types: • Alpha Radiation • Beta Radiation • Gamma Radiation
Alpha Radiation • Occurs when a helium nuclei is emitted • Called “alpha” particals • Product atoms atomic # is lower by 2 & its mass # is lower by 4 • Are stopped by paper!
Beta Radiation • e- released when a nucleus breaks apart • Product atom has the same atomic mass, but the atomic # increases by 1 • Less mass than an alpha particle & can penetrate paper, but are stopped by wood or aluminum foil
Gamma Radiation • High energy photons • Electromagnetic radiation • Have no mass or charge, so atomic # is unchanged • VERY DANGEROUS! • Can penetrate even wood!
Nuclear Decay • Nuclear force Attractive force between protons & neutrons that are really close together in the nucleus • Stronger than the electromagnetic repulsions • Keeps nucleus together!
Half-Life • Time it takes for half of the nuclei to decay into its stable daughter