1. Unit: Nuclear Chemistry
Day 3 – Notes
Unit: Nuclear Chemistry
Transmutations
Pictures starting from upper right moving left: Radioactivity symbol, particle accelerator, mushroom cloud (nuclear explosion), Marie and Pierre Curie, cooling tower of nuclear power plant

2. After today you will be able to…
Identify and explain two ways in which transmutations can occur.
Balance nuclear reactions.

3. al∙che∙my [al-kuh-mee] noun:
a science that was used in the Middle Ages with the goal of changing ordinary metals into gold
-Courtesy of Merriam-Webster (2015)

4. A brief history…
The modern practice of chemistry started in medieval Europe and the Middle East.
Alchemists (~16th century) believed that by doing certain chemical reactions, you could turn cheap metals into gold.
We now know that no chemical reaction can achieve this goal.
5:10 video – ACS

5. However, through transmutations modern chemists can change one element into another.

6. Transmutation Reactions
Transmutation: The conversion of an atom of one element to an atom of another element.
Can occur in two ways:
Radioactive decay
When the nucleus of an atom is bombarded with certain types of particles (proton, alpha, etc.)

7. Transmutation Reactions
Many transmutations occur in nature.
Example: C-14 is made from N-14 in the upper atmosphere. N 14 7 n 1 + C 14 6 + p 1

8. Transmutation Reactions
Many other transmutations are done in laboratories.
Example: The first artificial transmutation was done by Rutherford (1919).
Eventually led to the discovery of the proton. N 14 7 He 4 2 + F 18 9

9. Writing Transmutation Reactions
Transmutation reactions are written using the following guidelines:
Make sure the sum of the mass numbers (top left) is the same on both sides of the equation.
Make sure the sum of the atomic numbers (bottom left) is the same on both sides of the equation.

10. He or α e or β γ n H or p or β e Particle Symbol Alpha Beta Gamma
Be familiar with the following particles and their notations:
Particle
Symbol
Alpha
Beta
Gamma
Neutron
Proton
Positron He 4 2 or α 4 2 e -1 or β -1 γ n 1 H 1 or p 1 or β +1 e +1

11. Writing Transmutation Reactions
Example: Identify the missing information. Pu
239 94 He 4 2 + ?
242 96 Cm ? n 1 +

12. Writing Transmutation Reactions
Example: Identify the missing information. 12 6 U
238 92 ? + C
246 98 Cf + 4 n 1

13. Writing Transmutation Reactions
Example: Write the beta decay for carbon-14. 14 6 C e -1 + N 14 7

14. Writing Transmutation Reactions
Example: Write the alpha decay for radon-222.
222 86 Rn He 4 2 + Po
218 84

15. Transuranium Elements
Elements in the Periodic Table with atomic numbers above 92 are called transuranium elements.
All of these elements undergo transmutation, do not occur in nature, and are synthesized in the laboratory.
To synthesize these elements, particle accelerators bombard nuclei with fast moving particles.

16. Particle Accelerator:

17. Questions?
Begin WS3