2. Nuclear Chemistry

3. The Atom The atom consists of two parts: 1. The nucleus which contains: 2. Orbiting electrons. protons neutrons Multiple nuclei is called nucleons = Nuclide

4. X A Z Mass number Atomic number Element symbol = number of protons + number of neutrons = number of protons

5. U 235 92 U 238 92 There are many types of uranium: Mass # Atomic # Number of protons Number of neutrons Mass # Atomic # Number of protons Number of neutrons 235 92 143 146 92 238

6. Same number of protons but different number of neutrons is a….. ISOTOPE

7. Most naturally occurring isotopes are stable.

8. Atoms want to be stable

9. Ratio of p + to n 0 determines…. Nucleus Stability

10. Radioactive Decay (radioactivity) Unstable nuclei decomposes into stable nuclei, this is called…

11. an alpha particle (  ), a beta particle (  ), or a gamma ray  Radioactive Decay emits:

12. An alpha particle is identical to that of a helium nucleus. It contains two protons and two neutrons. Alpha Decay He 4 2

13. Alpha Decay Ra 226 88 Rn 222 86 He 4 2

14. X A Z Y A - 4 Z - 2 + He 4 2 Alpha Decay unstable atom more stable atom alpha particle

15. Alpha Decay 222 86 Rn Ra 226 88 + He 4 2 Ra 226 88 + He 4 2 Th 230 90 U 234 92 Th 230 90 + He 4 2

16. Alpha Decay + Pb 214 82 He 4 2 Po 218 84 Rn 222 86 Po 218 84 + He 4 2

17. Symbol CompositionRangeShield Alpha Particle He or α Helium Beta Particle Gamma Ray short Paper, skin

18. Beta Decay is a fast moving electron. Created when a n 0 changes into a p + & e -

19. Beta Decay Po 218 84  0 At 218 85

20. X A Z Y A Z + 1 +  0 Beta Decay unstable atom more stable atom beta particle

21. Beta Decay Pa 234 91 Th 234 90 +  0 At 218 85 Po 218 84 +  0

22. Beta Decay Bi 210 83 Po 210 84 +  0 -1 Pb 210 82 Tl 210 81 +  0 Bi 214 83 +  0 Pb 214 82

23. Symbol CompositionRangeShield Alpha Particle He or α Helium Beta Particle e - or β Electron Gamma Ray short Paper, skin Heavy Clothing, glass, light metals, plastic

24. Gamma Decay Not a charged particle it is energy. Electromagnetic radiation with high frequency

25. Draw the correct wave

26. Symbol CompositionRangeShield Alpha Particle He or α Helium Beta Particle e - or β Electron Gamma Ray  Photons (electromagnetic spectrum) short Paper, skin Heavy Clothing, glass, light metals, plastic Long Lead or concrete

27. Half Life: Time for half of the radioactive nuclide to decay 1. How much of a 100 g sample of 198 Au is left over 8.10 days if its half-life is 2.70 days?

28. 2. A 50.0 g sample of 16 N decays to 12.5 g in 14.4 seconds. What is the half-life?

29. 3. The half life of 42 K is 12.4 hours. How much of a 750g sample is left over after 62.0 hours?

30. 4. What is the half-life of 99 Tc if a 500 g sample decays to 62.5g in 639, 000 years?

31. 5. There are 5.0 g of 131I left after 40.35 days. How many grams were in the original sample if its half-life is 8.07 days?