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Nuclear Chemistry.

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Presentation on theme: "Nuclear Chemistry."— Presentation transcript:

1 Nuclear Chemistry

2 Nuclear Symbols Mass number, A (p+ + no) Element symbol
Atomic number, Z (number of p+)

3 Balancing Nuclear Equations
Areactants = Aproducts = (1) = (0) Zreactants = Zproducts

4 Balancing Nuclear Equations #2
222 226 = 4 + ____ 222 Rn 86 88 = 2 + ___ 86 Atomic number 86 is radon, Rn

5 Balancing Nuclear Equations #3
95 = (1) + ____ 95 Y 39 39 = (0) + ____ Atomic number 39 is yttrium, Y

6 Alpha Decay Alpha production (a): an alpha particle is a
helium nucleus Alpha decay is limited to heavy, radioactive nuclei

7 Alpha Radiation Limited to VERY large nucleii.

8 Beta Decay Beta production (b): A beta particle is an
electron ejected from the nucleus Beta emission converts a neutron to a proton

9 Beta Radiation Converts a neutron into a proton.

10 Gamma Ray Production Gamma ray production (g):
Gamma rays are high energy photons produced in association with other forms of decay. Gamma rays are massless and do not, by themselves, change the nucleus

11 Deflection of Decay Particles
Opposite charges_________ each other. attract Like charges_________ each other. repel

12 Positron Production Positron emission:
Positrons are the anti-particle of the electron Positron emission converts a proton to a neutron

13 Electron Capture Electron capture: (inner-orbital electron is captured by the nucleus) Electron capture converts a proton to a neutron

14 Types of Radiation

15 Nuclear Stability Decay will occur in such a way as to return a nucleus to the band (line) of stability. The most stable nuclide is Iron-56 If Z > 83, the nuclide is radioactive

16 A radioactive nucleus reaches a stable state by a series of steps
A Decay Series

17 Half-life Concept

18 Decay Kinetics Decay occurs by first order kinetics (the rate of decay is proportional to the number of nuclides present) N0 = number of nuclides present initially N = number of nuclides remaining at time t k = rate constant t = elapsed time

19 Calculating Half-life
t1/2 = Half-life (units dependent on rate constant, k)

20 Sample Half-Lives

21 Nuclear Fission and Fusion
Fusion: Combining two light nuclei to form a heavier, more stable nucleus. Fission: Splitting a heavy nucleus into two nuclei with smaller mass numbers.

22 Energy and Mass Nuclear changes occur with small but measurable losses of mass. The lost mass is called the mass defect, and is converted to energy according to Einstein’s equation: DE = Dmc2 Dm = mass defect DE = change in energy c = speed of light Because c2 is so large, even small amounts of mass are converted to enormous amount of energy.

23 Fission

24 Fission Processes A self-sustaining fission process is called a chain reaction.

25 A Fission Reactor

26 Fusion

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