1. CHAPTER 22 Nuclear Chemistry

2. Important Vocab
Nucleon – any particle found in the nucleus (includes protons and neutrons)
Nuclide – what atoms are referred to in nuclear chemistry

3. Mass Defect
Difference between the mass of an atom and the mass of its individual particles.
amu
amu
Notice that the atom has LESS mass than the separate particles. Matter is converted to energy when the atom is formed!

4. Nuclear Binding Energy
Energy released when a nucleus is formed from nucleons.
High binding energy = stable nucleus.
E = mc2
E: energy (J)
m: mass defect (kg)
c: speed of light (3.00×108 m/s)

5. Band of Stability
Make some observations!

7. Lighter nuclides are more stable with a 1:1 n0 : p+ ratio
Heavier nuclides are more stable with a 1.5:1 n0 : p+ ratio

8. F ission splitting a nucleus into two or more smaller, stable nuclei
1 g of 235U = 3 tons of coal

9. F ission
chain reaction - reaction in which the starting material is also one of the products and can start another reaction
critical mass - mass required to sustain a chain reaction
Nuclear power plants use fission

11. Fusion combining of two nuclei to form one nucleus of larger mass
thermonuclear reaction – requires temp of 40,000,000 K to sustain
1 g of fusion fuel = 20 tons of coal
occurs naturally in stars

12. Fission vs. Fusion FISSION FUSION -Can produce radioactive
waste and is dangerous
-Less energy is released
-The splitting of two or
more atoms -Limited U-235
-Does not take a lot of
energy to occur
FUSION
-Much safer, doesn’t produce radioactive waste
-More energy is released during the reaction
-The fusing of two or
more atoms -Abundant fuel
-Takes a lot of
Energy
releasing reaction
Nuclear
chain reactions
Used in nuclear weapons
Give off massive amounts of radioactivity and heat

13. More vocab
Radioactive decay – spontaneous disintegration of a nucleus into a lighter, more stable nucleus
Radioactive nuclide – an unstable nucleus that undergoes radioactive decay

14. B. Nuclear Decay Why nuclides decay… To become more stable
Reach the band of stability
DECAY SERIES TRANSPARENCY

15. Half-life Half-life (t½)
Time required for half the atoms of a radioactive nuclide to decay.
Shorter half-life = less stable.

16. Solve the following problems
The half life of polonium-210 is days. How many milligrams of polonium-210 remain after days, if you start with 2.0 mg of the isotope?

17. Assuming a half-life of 1599 years, how many years will be needed for the decay of 15/16 of a given amount of radium-226?

18. 3. The half-life of polonium-218 is 3. 0 minutes
3. The half-life of polonium-218 is 3.0 minutes. If you start with 16 mg, how long will it be before only 1.0 mg remains?

19. 4. If it takes 63 hours for 20. g to decay to 2
4. If it takes 63 hours for 20.g to decay to 2.5g, what is the half-life?

20. Properties of Radioactive Particles
Type
Symbol
Charge
Blocked by
Mass
alpha, α
Helium Nuclide
2 4 𝐻𝑒  
+2 
Paper or skin  4
Beta, β
electrons
−1 0 𝛽  
 -1
Metal foil   0
Gamma, γ
 photons
0 0 𝛾 0 
 Concrete or lead (not completely)

21. A. Types of Radiation 2+ 1- 1+ Alpha particle () helium nucleus
paper 2+
Beta particle (-)
electron 1-
lead
Positron (+)
positron 1+
concrete
Gamma ()
high-energy photon

22. Energy of the particles
Alpha particles have the least energy.
Gamma particles have the most energy.
Positrons are similar to beta particles in terms of energy and what it is blocked by.

23. Alpha Particle Emission
Sometimes called Alpha Decay Releases an alpha particle. Alpha particle will be a product. Mass number and atomic number decreases. Example:

24. Beta Particle Emission
Sometimes called Beta Decay An electron is emitted from a nucleus. The beta particle (or electron) will be a product. Example:

25. Electron Capture
An inner orbital electron is captured by the nucleus, look for an electron as a reactant (this is NOT a beta particle!) Example:

26. Alpha Bombardment
Nuclear reaction is forced by “bombarding” the nuclide with alpha particles. Look for an alpha particle as a reactant.
Example: 𝐴𝑙 𝐻𝑒 → 𝑃 𝑛

27. Positron Emission
A positive particle with no mass is emitted from the nucleus.
A positron is basically a positively charged electron
Example: 𝐾 → 𝐴𝑟 𝑒

28. Gamma Emission
High energy electromagnetic radiation is released from a nucleus, usually follows some other type of decay Example: 𝐶𝑜 → 𝐶𝑜 𝛾

29. Complete the following nuclear reactions and classify reaction type:
5 8 𝐵 → +1 0 𝛽 +_______
𝐼 → 𝑋𝑒 +________

30. Balancing Nuclear Reactions
Write a balanced nuclear equation for the alpha decay of thorium-230.

31. Complete the following rxns and classify:

32. Complete the following rxns and classify: ANSWERS
𝑃𝑏 alpha decay
−1 0 𝑒 electron capture
𝑀𝑑 alpha bombardment
𝑃𝑏 alpha decay
6 12 𝐶 alpha bombardment
−1 0 𝑒 electron capture

33. Nuclear Decay Transmutation – one element becomes another.
Parent nuclide – The isotope on the reactant side
Daughter nuclide – The isotope on the product side

35. Decay Series Write the decay for Radon-220.
What type of decay are all the diagonal arrows?

36. Decay Series Write the decay for Bismuth-212.
What type of decay are all the right arrows?

37. Decay Series
Write the decay series from Polonium-216 to Thallium-208

38. Test Topics All vocab Nuclear reaction types (including bombardment)
Properties of radiation
Half-life calculations
Fusion vs. Fission
Band of stability
Decay series (interpreting and writing reactions)
History of nuclear chemistry
Uses of nuclear reactions
Units and instruments used to measure
Nuclear power plants
Thermo/equilibrium stuff