1. Nuclear Chemistry
Chapter 21

2. Nuclear Chemistry
Study of nuclear reactions and their uses in chemistry
nuclear reactions – change in matter originating in the nucleus of an atom
radioactive – nuclei spontaneously changing and emitting radiation

3. Nuclear Chemistry Subatomic particles are involved
proton and neutron  nucleons
Can be determined by atomic number and mass number
Same atomic number, different mass number  isotope
Radioactive nuclei  radionuclide
Atoms with radionuclides  radioisotopes

4. Nuclear Chemistry Radionuclides Radioactive decay Unstable
Emit particles and electromagnetic radiation
Radioactive decay

5. Radioactive Decay 1 – alpha radiation α
Helium - 4 particles, aka alpha particles
42He
23892U  23490Th + 42He

6. Alpha radiation - Sample
What product is formed when radium-226 undergoes alpha decay?
22688Ra  22286Rn + 42He
What element undergoes alpha decay to form lead-208?
21284Po  20882Pb + 42He

7. Radioactive decay 2 – beta radiation β High speed e- 0-1e or 0-1 β
13153I  13154Xe + 0-1e

8. Radioactive decay 3 – gamma radiation γ High energy photons 00γ
Energy lost when nucleons reorganize

9. Radioactive decay 4 – positron emission
Same mass as e-, opposite charge
01e
116C  115B + 01e
Positron can convert proton to neutron

10. Radioactive decay 5 – electron capture
Capture of electron by nucleus from electron cloud
0-1e consumed, not formed

11. Electron Capture - Sample
Write nuclear equations for the following processes:
a) Mercury-201 undergoes electron capture
b) Thorium-231 decays to form protactinium-231
a) 20180Hg + 0-1e  20179Au
b) 23190Th  23191Pa + 0-1e

12. Electron Capture-Sample 2
Write a balanced nuclear equation for the reaction in which oxygen-15 undergoes positron emission
158O  157N + 01e

13. Nuclear Transmutations
Nuclei changed by being struck by neutron or nucleus
Commonly represented by listing in order the target nucleus, the bombarding particles, the ejected particles, the product nucleus
147N (α,p)178O
147N + 42He  11p + 178O

14. Nuclear Transmutations-Sample
Write the balanced nuclear equation for the process summarized as 2713Al (n, α) 2411Na
2713Al + 10n  42He Na
Using shorthand notation, write the nuclear reaction 168O + 11H  137N + 42He
168O (p, α) 42He