1. The Nucleus: A Chemist’s View Chapter 20 E-mail: benzene4president@gmail.combenzene4president@gmail.com Web-site: http://clas.sa.ucsb.edu/staff/terri/

2. The Nucleus: A Chemist’s View 1. Supply the missing particle for each of the following nuclear reactions: a. 73 Ga  73 Ge + ? b. 192 Pt  188 Os + ? c. 205 Bi  205 Pb + ? d. 241 Cm + ?  241 Am

3. The Nucleus: A Chemist’s View

4. 2. Write an equation for each of the following: a. 68 Ga undergoing electron capture b. 62 Cu undergoing positron emission c. 212 Fr undergoing alpha decay d. 129 Sb undergoing beta decay

5. The Nucleus: A Chemist’s View 3. The radioactive isotope 247 Bk decays by an alpha and beta series ending in 207 Pb. How many alpha and beta particles were emitted in the series? What is the daughter nucleus if 242 U underwent a decay series producing 4 alpha and 3 beta particles?

6. The Nucleus: A Chemist’s View 4. The only stable isotope of fluorine is fluorine-19. Predict possible modes of decay for fluorine-21 and fluorine-18.

7. The Nucleus: A Chemist’s View 5. The first atomic explosion was detonated on July16, 1945. What fraction of the strontium-90 (t 1/2 = 28.8 yr) will remain as of July 16, 2014?

8. The Nucleus: A Chemist’s View 6. The sun radiates 3.9 x 10 23 J of energy into space every second. What is the rate at which mass is lost from the sun?

9. The Nucleus: A Chemist’s View 7. A freshly isolated sample of 90 Y was found to have an activity of 9.8×10 5 disintegrations per minute at 1:00 pm on December 3, 2000. At 2:15 pm on December 17, 2000, its activity was redetermined and found to be 2.6×10 4 disintegrations per minute. Calculate the half-life of 90 Y.

10. The Nucleus: A Chemist’s View 8. Phosphorus-32 is a commonly used radioactive nuclide in biochemical research. The half-life of phosphorus-32 is 14.3 days. What mass of phosphorus-32 is left from an original sample of 175 mg of Na 3 32 PO 4 after 35.0 days? Assume the atomic mass of 32 P is 32.0.

11. The Nucleus: A Chemist’s View 9. A rock contains 0.688 mg of 206 Pb for every 1.000 mg of 238 U present. Calculate the age of the rock (t 1/2 = 4.5x10 9 yr). Assume that no lead was present in the original rock.

12. The Nucleus: A Chemist’s View 10. The most stable nucleus in terms of binding energy per nucleon is 56 Fe. If the atomic mass of 56 Fe is 55.9349 amu, calculate the binding energy per nucleon for 56 Fe. (neutron = 1.67493 x 10 -27 kg, proton = 1.67262 x 10 -27 kg, electron = 9.10939 x 10 -31 kg)

13. The Nucleus: A Chemist’s View 11. A positron and an electron annihilate each other upon colliding, thereby producing energy in the form of 2 photons. Calculate the wavelength of the light produced. (mass of an electron = 9.10939 x10 -31 kg)

14. The Nucleus: A Chemist’s View

17. 4. The only stable isotope of fluorine is fluorine-19. Predict possible modes of decay for fluorine-21 and fluorine-18. If F-19 is stable then F-21 is neutron rich and will undergo beta decay – whereas F-18 is proton rich an will either undergo positron emission or electron capture

18. The Nucleus: A Chemist’s View

19. 6. The sun radiates 3.9 x 10 23 J of energy into space every second. What is the rate at which mass is lost from the sun? Fusion occurs on the sun – fusion is the combining of 2 small nuclei into 1 nucleus – a small amount of matter is converted to E due to making a strong force in the nucleus ΔE = Δmc 2

20. The Nucleus: A Chemist’s View