1. Lesson 1: Islands of Stability
Nuclear Chemistry
Lesson 1:
Islands of Stability

2. Nuclear Chemistry – Bell work
The isotope notation for an atom of copper and an atom of gold are given below:
How could you change a copper atom into a gold atom?
What would you need to change? Give specific numbers.
Why is this change called a nuclear reaction? Cu 63 29 Au
197 79

3. The Big Question
What is the range of the number of neutrons found in isotopes of various elements?
Goal - Determine how many neutrons are required to make a stable element with a given number of protons.

4. Plot this isotope # of protons? # of neutrons?
Island of stability
Plot this isotope # of protons? # of neutrons?
protons = neutrons
Band of stability

5. Notes Nuclear chemistry study of atom nucleus
Band of stability range in neutron # for given proton # for naturally occurring isotopes

6. Stable isotope? Inside gray area? Stable isotope On edge? Radioactive
Outside?
Isotope not stable
Not an element
What is an element?
Isotope detected?
Element 118 discovery last fall
Lasted 0.05 milliseconds

7. > s 
10-01 s
10+10 s 
10-02 s
10+07 s 
10-03 s
10+05 s 
10-04 s
10+04 s 
10-05 s
10+03 s 
10-06 s
10+02 s 
10-07 s
10+01 s 
10-15 s
10+00 s 
< s

8. p = 12 n = 12 p = 92 n = 60 p = 118 n = 77 p = 35 n = 55 p = 92 n = 146 p = 77 n = 114

9. p = 12 n = 12 p = 60 n = 92 p = 77 n =118 p = 35 n = 55 p = 92 n = 146 p = 77 n = 114

10. Worksheet
Imagine a chemist was trying to create an atom with 60 protons and a mass number of 155. Would this be possible? Why or why not?
Where on the graph would you expect the other isotopes of magnesium to be located (magnesium-25 and magnesium-26)? Explain.

11. Worksheet
If an element had 90 protons, how many neutrons would be a good number for it to have in order to be considered a stable element? What element would this be?
What do you suppose that little island of gray on the graph represents?

12. Check-In
Use your graph to determine how many neutrons you would need to make a stable element with 75 protons.
How many neutrons would make a radioactive element with 75 protons?

13. Answer to #10
No Yes Yes No Yes

14. Notes Radioactive elements lose pieces of the nucleus over time.
Atoms that exist for a long time are called stable.
Radioactive atoms disappear over time and are called unstable.
Any isotope that lasts long enough to be detected and measured qualifies as an element
Element 118 discovery last fall
0.05 milliseconds