Radioactivity        Spontaneous emission of particles and or radiation.                     (name invented by Marie Curie...
–α                 Lead blockγβ    +        Radioactive substance
–    Lead block+
–α                 Lead block    +        Radioactive substance
–                  Lead blockβ    +        Radioactive substance
–                  Lead blockγ    +        Radioactive substance
–α                 Lead blockγβ    +        Radioactive substance
Penetrating Ability
Stability  of Nuclei• Out of > 300 stable isotopes:         N   Even    Odd    Z   Even      157     52                 31...
Atomic number (Z) = number of protons in nucleus Mass number (A) = number of protons + number of neutrons                 ...
Balancing Nuclear Equations1. Conserve mass number (A).The sum of protons plus neutrons in the products must equalthe sum ...
Po decays by alpha emission. Write the balanced212nuclear equation for the decay of 212Po.         alpha particle - 2He or...
23.1
I. Nuclear Stability and Radioactive Decay
n/p too large beta decay X                Y             n/p too small     positron decay or electron capture              ...
Stability  of Nuclei• Out of > 300 stable isotopes:         N   Even    Odd    Z   Even      157     52                 31...
Predicting the mode of decay1. High n/p ratio (too many neutrons; lie above band   of stability) --- undergoes beta decay2...
II. Nuclear Transmutations •Nuclear reactions that are induced in a way that nucleus is struck by a neutron or by another ...
Transuranium elements-Element with atomic numbers above 92-Produced using artificial transmutations, eitherby:    a. alpha...
III. Nuclear EnergyRecall:Nucleus is composed of proton and neutronThen, is the mass of an atom equal to the total mass of...
Mass defect   -mass difference due to the release of energy   -this mass can be calculated using Einstein’s equation   E =...
Nuclear binding energy per nucleon vs Mass number    nuclear binding energy                             nuclear stability ...
-The plot shows the use of nuclear reactions as source ofenergy.-energy is released in a process which goes from ahigher e...
Nuclear binding energy (BE) is the energy required to break up a nucleus into its component protons and neutrons.         ...
23.3
Radiocarbon Dating      14       7 N + 0n             1            14                           6C + 1H                   ...
Nuclear Fission             235             92 U + 0n                    1         90                              38Sr + ...
Nuclear Fission      Representative fission reaction23592 U + 0n       1       90               38Sr + 143Xe + 310 + Energ...
Nuclear FissionNuclear chain reaction is a self-sustaining sequence ofnuclear fission reactions.The minimum mass of fissio...
Nuclear Fission                    Schematic                   diagram of a                  nuclear fission              ...
Nuclear Fission     35,000 tons SO2               Annual Waste Production    4.5 x 106 tons CO2                           ...
Nuclear Fusion   Fusion Reaction             Energy Released21 H + 1H      2             1H + 1H             3    1       ...
Radioisotopes in Medicine•   1 out of every 3 hospital patients will undergo a nuclear    medicine procedure•   24        ...
Geiger-Müller Counter                        23.7
Biological Effects of Radiation              Radiation absorbed dose (rad)              1 rad = 1 x 10-5 J/g of material  ...
Chemistry In Action: Food IrradiationDosage                    Effect                          Inhibits sprouting of potat...
Nuclearchemistrypowerpoint Slideshare
Nuclearchemistrypowerpoint Slideshare
Nuclearchemistrypowerpoint Slideshare
Nuclearchemistrypowerpoint Slideshare
Nuclearchemistrypowerpoint Slideshare
Nuclearchemistrypowerpoint Slideshare
Nuclearchemistrypowerpoint Slideshare
Nuclearchemistrypowerpoint Slideshare
Nuclearchemistrypowerpoint Slideshare
Upcoming SlideShare
Loading in …5
×

Nuclearchemistrypowerpoint Slideshare

326 views

Published on

For Chemistry 150

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
326
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
0
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Nuclearchemistrypowerpoint Slideshare

  1. 1. Radioactivity Spontaneous emission of particles and or radiation. (name invented by Marie Curie for a discovery of Henri Becquerel 1896) •“Rays” of three types are produced by the decay, or breakdown, of radioactive substances1. Alpha rays ( α ) – consist of positively helium nuclei and thus are deflectedin an external magnetic and electric fields.2. Beta rays ( β ) – are electrons and thus are deflected in an externalmagnetic and electric fields.3. Gamma rays ( γ ) – are “light” (electromagnetic radiation) and thus are notaffected by an external electric field or magnetic field
  2. 2. –α Lead blockγβ + Radioactive substance
  3. 3. – Lead block+
  4. 4. –α Lead block + Radioactive substance
  5. 5. – Lead blockβ + Radioactive substance
  6. 6. – Lead blockγ + Radioactive substance
  7. 7. –α Lead blockγβ + Radioactive substance
  8. 8. Penetrating Ability
  9. 9. Stability of Nuclei• Out of > 300 stable isotopes: N Even Odd Z Even 157 52 31 P 15 Odd 50 5 19 F 9 2 1 H, 63Li, 105B, 147N, 18073Ta
  10. 10. Atomic number (Z) = number of protons in nucleus Mass number (A) = number of protons + number of neutrons = atomic number (Z) + number of neutrons Mass Number A ZX Element Symbol Atomic Number proton neutron electron positron α particle 1 1 p or 1H 1 0n 1 0 -1 e or -1β 0 0 +1 e or +1β 0 4 2 He or 2α 4A 1 1 0 0 4Z 1 0 -1 +1 2 23.1
  11. 11. Balancing Nuclear Equations1. Conserve mass number (A).The sum of protons plus neutrons in the products must equalthe sum of protons plus neutrons in the reactants. 235 138 96 92 U + 0n 1 55 Cs + 37 Rb + 2 0n 1 235 + 1 = 138 + 96 + 2x12. Conserve atomic number (Z) or nuclear charge.The sum of nuclear charges in the products must equal thesum of nuclear charges in the reactants. 235 138 96 92 U + 0n 1 55 Cs + 37 Rb + 2 0n 1 92 + 0 = 55 + 37 + 2x0 23.1
  12. 12. Po decays by alpha emission. Write the balanced212nuclear equation for the decay of 212Po. alpha particle - 2He or 2α 4 4 84Po He + AX 212 4 2 Z 212 = 4 + A A = 208 84 = 2 + Z Z = 82 84 Po 2He + 208Pb 212 4 82 23.1
  13. 13. 23.1
  14. 14. I. Nuclear Stability and Radioactive Decay
  15. 15. n/p too large beta decay X Y n/p too small positron decay or electron capture 23.2
  16. 16. Stability of Nuclei• Out of > 300 stable isotopes: N Even Odd Z Even 157 52 31 P 15 Odd 50 5 19 F 9 2 1 H, 63Li, 105B, 147N, 18073Ta
  17. 17. Predicting the mode of decay1. High n/p ratio (too many neutrons; lie above band of stability) --- undergoes beta decay2. Low n/p ratio (neutron poor; lie below band of stability) --- positron decay or electron capture3. Heavy nuclides ( Z > 83) --- alpha decay
  18. 18. II. Nuclear Transmutations •Nuclear reactions that are induced in a way that nucleus is struck by a neutron or by another nucleus (nuclear bombardment) a.Positive ion bombardment - alpha particle is the most commonly used positive ion - uses accelerators Examples: 7 N + 2 He → 8 O + 1H 14 4 17 1 9 4 Be + 42 He → 126 C + 10n b.Neutron bombardment - neutron is bombarded to a nucleus to form a new nucleus - most commonly used in the transmutation to form synthetic isotopes because neutron are neutral, they are not repelled by nucleus Example: 26 Fe + 0 n → 26 Fe → 27 Co + -1 e 58 1 59 59 0
  19. 19. Transuranium elements-Element with atomic numbers above 92-Produced using artificial transmutations, eitherby: a. alpha bombardment b. neutron bombardment c. bombardment from other nuclei Examples: 239 242 94 Pu + 2He + 1n 4 a. 96 Cm 0 238 239 b. 92 U + 0n 1 92 U 239 239 94 Pu+ -1 e 0 93 Np + 0 -1 e 238 N 247 c. 92 U + 14 7 99 Es + 5 0n 1
  20. 20. III. Nuclear EnergyRecall:Nucleus is composed of proton and neutronThen, is the mass of an atom equal to the total mass ofall the proton plus the total mass of all the neutron?Example for a He atom:Total mass of the subatomic particles= mass of 2 p+ + mass of 2n0= 2 ( 1.00728 amu ) + 2 (1.00867 amu)= 4.03190 amuAnd atomic weight of He-4 is 4.00150Why does the mass differ if the atomic mass = numberof protons + number of neutrons?
  21. 21. Mass defect -mass difference due to the release of energy -this mass can be calculated using Einstein’s equation E =mc2 2 11 H + 2 20 H → 42 He + energy Therefore: -energy is released upon the formation of a nucleus from the constituent protons and neutrons -the nucleus is lower in energy than the component parts. -The energy released is a measure of the stability of the nucleus. Taking the reverse of the equation: 2 He + energy → 2 1 H + 2 0 n 4 1 2
  22. 22. Nuclear binding energy per nucleon vs Mass number nuclear binding energy nuclear stability nucleon 23.2
  23. 23. -The plot shows the use of nuclear reactions as source ofenergy.-energy is released in a process which goes from ahigher energy state (less stable, low binding energy) to alow energy state (more stable, high binding energy).-Using the plot, there are two ways in which energy canbe released in nuclear reactions: a. Fission – splitting of a heavy nucleus intosmaller nuclei b. Fusion – combining of two light nuclei to form aheavier, more stable nucleus.
  24. 24. Nuclear binding energy (BE) is the energy required to break up a nucleus into its component protons and neutrons. BE + 19F 9 91p + 101n 1 0 E = mc2 BE = 9 x (p mass) + 10 x (n mass) – 19F massBE (amu) = 9 x 1.007825 + 10 x 1.008665 – 18.9984 BE = 0.1587 amu 1 amu = 1.49 x 10-10 J BE = 2.37 x 10-11J binding energybinding energy per nucleon = number of nucleons 2.37 x 10-11 J = = 1.25 x 10-12 J 19 nucleons 23.2
  25. 25. 23.3
  26. 26. Radiocarbon Dating 14 7 N + 0n 1 14 6C + 1H 1 6C 14 14 7 N + -1β + ν 0 t½ = 5730 yearsUranium-238 Dating 92 U 238 206 82Pb + 8 4α + 6 -1β 2 0 t½ = 4.51 x 109 years 23.3
  27. 27. Nuclear Fission 235 92 U + 0n 1 90 38Sr + 143Xe + 310 + Energy 54 nEnergy = [mass 235U + mass n – (mass 90Sr + mass 143Xe + 3 x mass n )] x c2 Energy = 3.3 x 10-11J per 235U = 2.0 x 1013 J per mole 235U Combustion of 1 ton of coal = 5 x 107 J 23.5
  28. 28. Nuclear Fission Representative fission reaction23592 U + 0n 1 90 38Sr + 143Xe + 310 + Energy 54 n 23.5
  29. 29. Nuclear FissionNuclear chain reaction is a self-sustaining sequence ofnuclear fission reactions.The minimum mass of fissionable material required togenerate a self-sustaining nuclear chain reaction is thecritical mass. Non-critical Critical 23.5
  30. 30. Nuclear Fission Schematic diagram of a nuclear fission reactor 23.5
  31. 31. Nuclear Fission 35,000 tons SO2 Annual Waste Production 4.5 x 106 tons CO2 70 ft3 3.5 x 106 vitrified ft3 ash waste1,000 MW coal-fired 1,000 MW nuclear power plant power plant 23.5
  32. 32. Nuclear Fusion Fusion Reaction Energy Released21 H + 1H 2 1H + 1H 3 1 6.3 x 10-13 J21 H + 1H 3 4 2 He + 1n 0 2.8 x 10-12 J6 Li + 1 H 2 2 4He 3.6 x 10-12 J3 2 Tokamak magnetic plasma confinement 23.6
  33. 33. Radioisotopes in Medicine• 1 out of every 3 hospital patients will undergo a nuclear medicine procedure• 24 Na, t½ = 14.8 hr, β emitter, blood-flow tracer• 131 I, t½ = 14.8 hr, β emitter, thyroid gland activity• 123 I, t½ = 13.3 hr, γ−ray emitter, brain imaging• 18 F, t½ = 1.8 hr, β+ emitter, positron emission tomography• 99m Tc, t½ = 6 hr, γ−ray emitter, imaging agent Brain images with 123I-labeled compound 23.7
  34. 34. Geiger-Müller Counter 23.7
  35. 35. Biological Effects of Radiation Radiation absorbed dose (rad) 1 rad = 1 x 10-5 J/g of material Roentgen equivalent for man (rem) 1 rem = 1 rad x Q Quality Factor γ-ray = 1 β=1 α = 20 23.8
  36. 36. Chemistry In Action: Food IrradiationDosage Effect Inhibits sprouting of potatoes, onions, garlics.Up to 100 kilorad Inactivates trichinae in pork. Kills or prevents insects from reproducing in grains, fruits, and vegetables. Delays spoilage of meat poultry and fish. Reduces100 – 1000 kilorads salmonella. Extends shelf life of some fruit. Sterilizes meat, poultry and fish. Kills insects and1000 to 10,000 kilorads microorganisms in spices and seasoning.

×