Nuclear Chemistry Nuclear ≠ Nucluar

Nuclear Reactions vs. Normal Chemical Changes Nuclear reactions involve the nucleus Protons and neutrons are rearranged Releases a tremendous amount of energy– called binding energy “Normal” Chemical Reactions involve electrons, not protons and neutrons

Types of Radiation Beta (β) – an electron Alpha (ά) – a helium isotope Beta (β) – an electron Gamma (γ) – pure energy; called a ray rather than a particle

Penetrating Ability

Other Types of Particles Neutron Proton Elements will correspond to their bottom number/number of protons Eg:

212Po decays by alpha emission 212Po decays by alpha emission. Write the balanced nuclear equation for the decay of 212Po. 4He 2 4a or alpha particle - 212Po 4He + AX 84 2 Z 212 = 4 + A A = 208 84 = 2 + Z Z = 82 212Po 4He + 208Pb 84 2 82 23.1

Nuclear Stability and Radioactive Decay Beta decay 14C 14N + 0b 6 7 -1 Decrease # of neutrons by 1 40K 40Ca + 0b 19 20 -1 Increase # of protons by 1 23.2

Nuclear Stability and Radioactive Decay 55Fe + 0e 55Mn + n 26 25 -1 Increase # of neutrons by 1 1p + 0e 1n + n 1 -1 Decrease # of protons by 1 Alpha decay Decrease # of neutrons by 2 212Po 4He + 208Pb 84 2 82 Decrease # of protons by 2

Learning Check What radioactive isotope is produced in the following bombardment of boron? 10B + 4He ? + 1n 5 2 0

Learning Check What radioactive isotope is produced in the following bombardment of boron? 10B + 4He 13N + 1n 5 2 7 0

Write Nuclear Equations! Write the nuclear equation for the beta emitter Co-60. 60Co 0e + ?? 27 -1 ?

Half-Life HALF-LIFE is the time that it takes for 1/2 a sample to decompose.

Half-Life Decay of 20.0 mg of 15O. What remains after 3 half-lives? After 5 half-lives?

Sample question How much U-238 is left over if a 100 gram sample undergoes 8 half lives?

Learning Check! The half life of I-123 is 13 hr. How much of a 64 mg sample of I-123 is left after 39 hours?

Last learning check What fraction of an unknown mass of Iodine, which has a half life of 8 hours, would you expect to be left after 72 hours?

Nuclear Fission Larger and unstable nuclei being bombarded with particles and breaking into smaller nuclei and releasing energy at the same time.

Mass Defect Some of the mass can be converted into energy Shown by a very famous equation! E=mc2 Energy Mass Speed of light

Nuclear Fusion Fusion Small nuclei combine to make larger nuclei and release TONS of energy 2H + 3H 4He + 1n + Energy 1 1 2 0

Nuclear Fusion Fusion Excessive heat can not be contained Attempts at “cold” fusion have FAILED. “Hot” fusion is difficult to contain

Summarize what you’ve learned