1. Physical Science

2. Sec 1: What is radioactivity? So what are the names of these particles? Positive particles? protons neutrons No charge, NEUtral

3. Sec 1: What is radioactivity? Bell ringer review: What is this structure made up of protons and neutrons? protons neutrons Atomic nucleus

4. Sec 1: What is radioactivity? What element is this? How do you know? 1.Count the number of protons. 2.The # of protons = the __________? 2

5. Sec 1: What is radioactivity? What element is this? How do you know? 1.Count the number of protons. 2.The # of protons = the Atomic Number 2 2 He 4

6. Sec 1: What is radioactivity? Complete the table to indicate how many protons and neutrons there are. P 32 15 Remember, the bottom # is the # of protons (+), or the atomic number. (Verify this on the periodic Chart.

7. Sec 1: What is radioactivity? Complete the table to indicate how many protons and neutrons there are. P 32 15 The top number is the mass number, or the atomic mass. Mass # = protons + neutrons so Mass # - protons = neutrons OR Mass # - atomic # = neutrons

8. Sec 1: What is radioactivity? Complete the table to indicate how many protons and neutrons there are. protonsneutrons 1517

9. Sec 1: What is radioactivity? Remember in chemical reactions there were always the same number of each type of atoms on each side of the arrow? 2H 2 + 0 2 → 2H 2 O Atoms were just rearranged. 4 H atoms

10. Sec 1: What is radioactivity? Remember in chemical reactions there were always the same number of each type of atoms on each side of the arrow? 2H 2 + 0 2 → 2H 2 O Atoms were just rearranged. 2 O atoms Balanced equation

11. Sec 1: What is radioactivity? But what would happen if an atom actually lost protons? P 32 15 ? 13 30 The atomic number would change! Change number of p+ means change in mass number too!

12. Sec 1: What is radioactivity? But what would happen if an atom actually lost protons? P 30 13 ? Note the change in atomic number. So the identity of the element will change!!!! Al 30 13

13. Sec 1: What is radioactivity? This is radioactivity! Radioactivity - the process by which an unstable nucleus emits one or more particles or energy in the form of electromagnetic radiation. - there are different types of radiation - this is only one example.

14. Sec 1: What is radioactivity? This is radioactivity! Radioactive Decay – the process by which an atomic nucleus loses nuclear mass becomes an isotope by losing neutrons becomes a different element by losing protons

15. Sec 1: What is radioactivity? Nuclear radiation the particles that are released from the nucleus during radioactive decay. Page 4 Types Nuclear Radiation You won’t need to memorize these values but you will need to know relative size.

16. Sec 1: What is radioactivity? I. Alpha Particle 1. Made of 2 protons and 2 neutrons 2. Charge of +2 3. Mass of 4 amu 4. Symbolized by - Basically it is a helium nucleus 5. Low energy, least penetrating form of radiation, stopped by sheet of paper or skin 6. Inside body can cause damage to bio-molecules. (Proteins, DNA) 7. Used in smoke detectors: 241 Am  (Alpha symbol)

17. Sec 1: What is radioactivity? Alpha Particle 8. Alpha Decay –atom loses 2 protons & 2 neutrons. Loss of mass results in new mass number. Loss of protons results in new element. An equation can be written:  Pu 240 94 U 236 92 He + 4 2

18. Sec 1: What is radioactivity? Writing equations for Alpha Decay Step 1: Write the nuclide notation for your starting material, Step 2: Write the nuclide notation for the particle released. Pu 240 94 He 4 2

19. Sec 1: What is radioactivity? Writing equations for Alpha Decay Step 1: Write the nuclide notation for your starting material, Step 2: Write the nuclide notation for the particle released. Pu 240 94 He 4 2 Step 3: Subtract the atomic mass units lost. 240 – 4 = 236 + 236

20. Sec 1: What is radioactivity? Writing equations for Alpha Decay Step 1: Write the nuclide notation for your starting material, Step 2: Write the nuclide notation for the particle released. Pu 240 94 He 4 2 Step 3: Subtract the atomic mass units lost. 240 – 4 = 236 Step 4: Subtract the protons lost. 94 – 2 = 92 + 236 92

21. Sec 1: What is radioactivity? Writing equations for Alpha Decay Step 1: Write the nuclide notation for your starting material, Step 2: Write the nuclide notation for the particle released. Pu 240 94 He 4 2 Step 3: Subtract the atomic mass units lost. 240 – 4 = 236 Step 4: Subtract the protons lost. 94 – 2 = 92 Step 5: Look up the new identity of the element and write the symbol. + 236 92 U Atomic number

22. Sec 1: What is radioactivity? When one element turns into another element by the process of radioactive decay this is called transmutation Pu 240 94 He 4 2 + 236 92 U

23. Anti-nutrino Sec 1: What is radioactivity? II. Beta decay 1. A neutron turns into a proton and emits an electron! e- This electron is called a Beta particle Symbol  -

24. Anti-nutrino Sec 1: What is radioactivity? II. Beta decay 1. A neutron turns into a proton and emits an electron! e- This electron is called a Beta particle Symbol  - You could draw a picture of the change that looked like this.

25. Sec 1: What is radioactivity? II. Beta decay 1.A neutron turns into a proton and emits an electron! 2.Beta particle symbol: e or  - 3.Charge: negative 4.Mass = 0 so the nuclide mass stays the same. 5.Higher energy that alpha particles, can pass through paper but stopped by aluminum foil. 6.Inside the body will damage cells. 7.Overall gain of one proton so transmutation has occurred. 0

26. Sec 1: What is radioactivity? Beta decay 7. Overall gain of one proton so transmutation has occurred. Example: C 14 6 e 0 + 14

27. Sec 1: What is radioactivity? Beta decay 7. Overall gain of one proton so transmutation has occurred. Example: C 14 6 e 0 + 14 7 N Remember you are subtracting so 6 – (-1) = 6 + 1 = 7

28. Sec 1: What is radioactivity? Beta decay Keep in mind that there is another type of Beta decay called Positron emission – you’ll learn about it in chemistry but we won’t worry about it right now. Free Information

29. Sec 1: What is radioactivity? III. Gamma Rays 1.symbol: 2.Electromagnetic rays (not matter) 3.The highest energy and shortest wavelength of the entire spectrum.   Rays have enough energy to penetrate skin, paper and even wood. Usually contained by concrete lined with lead.

30. Sec 1: What is radioactivity? III. Gamma Rays 1.symbol: 2.Electromagnetic rays (not matter) 3.The highest energy and shortest wavelength of the entire spectrum. 4.No mass or charge. 5.Travel at the speed of light. 6.May not cause as much damage to tissues because they do not carry a charge. 7.Useful in treating cancers by directing a beam of radiation at tumors. 99 Tc most widely used radio-isotope in medicine. 

31. Sec 1: What is radioactivity? III. Gamma Rays 8. Transmutation does not occur by gamma emission.

32. Sec 1: What is radioactivity? IV. Neutron emission 1.high energy neutrons emitted from a nucleus. 2.Neutron is matter and has mass 3.Relatively high energy, between beta and gamma particles, can penetrate concrete 4.occurs in heavy isotopes (He-5) and high mass radio active elements (Cf-252)

33. Sec 1: What is radioactivity? IV. Neutron emission 8. Transmutation does NOT occur... but change in mass number does due to loss of neutron.