1. Radiation

2. Radiation (Nuclear Decay)
First used by Marie Curie ( )
Radiation: Energy released
in the form of particle or electromagnetic waves.
Measured units:
rems/millirems

3. History 1903 Radiation 1942 First Chain Reaction 1895 X-rays
Nuclear Bomb
Wilhem Conrad Roentgen Robert Oppenheimer
1903 Radiation First Chain Reaction
In the 1800s, the discovery of photography ultimately lead to the splitting of the atom.
The basis of photography is that visible light causes certain chemical reactions – if the chemicals are spread thinly on a surface but protected from light by a covering, no reaction occurs. When the covering is removed, light acting on the chemicals causes them to darken.
Roentgen (rentgen) discovered that radiation other than visible light could expose photographic film – film wrapped in dark paper would react when x-rays went through the paper and struck the film.
Becqueurel discovered that uranium containing rocks could develop photographic plates – the radiation from the uranium had no connection with light or flouresence, directly proportional to the concentration of uranium
Maria Curie was one of Becqurel’s assistants – her and her husband decided to find out if other chemicals were radioactive – studied pitchblend (residue of uranium mining) from mining region in Austria – separated a previously known element radium – found it was many more times radioactive than uranium.
- They received the 1903 Novel Prize in Physics
- Marie Curie later won the 1911 Nobel Prize in Chemistry for her continued work with radioactivity
* She was the first female Nobel laureate and only person to ever receive 2 Nobel Prizes in 2 different scientific categories
Marie Curie
Enrico Fermi

4. Radiation is all around Us!!
Natural Background Radiation:
Cosmic Radiation – the earth, and all living things on it, are constantly bombarded with radiation from space (e.g. sun and stars)
Terrestrial Radiation – soil, water, and vegetation
Some are ingested with food and water
Some are inhaled (e.g. radon)
Internal Radiation (K-40, C-14, Pb-210)
Found in bodies from birth
** Radiation increases as altitudes increase

5. Man-made Radiation
Medical uses (X-rays, CAT and PET scans) – most significant source
Consumer products – tobacco, building materials, combustible fuels (gas, coal, etc.), tvs, luminous watches,
Smoke detectors (americium)
Lantern mantles (thorium)
Chernobyl (First year) and Japan fallout
Fallout from weapons testing
Job (Average) – radiography, x-ray techs, etc.
Nuclear Industry (Waste)

9. Electromagnetic Spectrum
Non-ionizing vs Ionizing Radiation

10. Particles more energy. They have a greater impact in the body
Smaller particles store
more energy. They
have a greater impact
in the body

11. Dose Response on Tissues
April 26, 2017
Dose Response on Tissues
Examples of tissue Sensitivity
Very High
White blood cells (bone marrow)
Intestinal epithelium
Reproductive cells
High
Optic lens epithelium
Esophageal epithelium
Mucous membranes
Medium
Brain – Glial cells
Lung, kidney, liver, thyroid, pancreatic epithelium
Low
Mature red blood cells
Muscle cells
Mature bone and cartilage
A Small Dose of Toxicology - Overview

12. Effects of Radiation

13. Even though we have learned about some harmful effects of radiation, have in mind the following ……..
Americans get about 25 mrems of radiation from food and water we eat each year.
This number varies depending what is eaten, where it is grown and how much is eaten.
E.g. Bananas and Brazil nuts contain higher proportions than most food.
Additional amounts of radiation come from man made sources
E.g. Mainly medical, dental, construction, and nuclear industry sources
Americans average between mrems of radiation from all sources each year.
Places in India and Brazil may have 3,000 mrems yearly.
Radiation levels of 50,000 mrems have not produced any evident ill effects
Strict safety standards on radiation exposure allow people to work in science, medicine, construction and nuclear power plants.

14. Activity # 2
**Answer Review Exercise – p.1 **Total Annual Millirems (mrems) Dose Worksheet. Keep in mind the following facts: 1. Question #2: Monterrey’s Elevation is 537m /1,762 ft 2. Question #7: Research miles traveled per year. Example: Mty-Cancun (Round Trip) = 1900miles 3. Research has shown that 50,000 mrems have not produced any evident ill effects

15. Nuclear Stability Nucleus contain Protons and Neutrons.
Contains a strong Electromagnetic
force to hold the Protons together.
Nucleus of some elements become
unstable releasing energy as the
form of radiation.

16. Radiation can be detected if it:
Alters a photographic film
Produces an electric charge in the surrounding air
Can produce fluorescence (glowing)

17. Isotopes
Atoms of an element with the same number of protons and a different number of neutrons.
Therefore their mass number is also different.

19. Other Isotopes

20. Analyzing Isotopes Complete the following table :
Write the nuclear symbol for atoms with the following subatomic particles:
8p, 8n, 8e =
17p, 20n, 17e =
47p, 60n, 47e =

21. Analyzing Isotopes Solutions
Complete the following table :
Protons
Neutrons
Electrons
Atomic #
Mass #
Write the nuclear symbol for atoms with the following subatomic particles:
A. 8p, 8n, 8e = O B p,20n, 47e = Cl
47p, 60n, 47e = Ag 47

22. Copper has two isotopes: Cu-63 and Cu-65
Copper has two isotopes: Cu-63 and Cu-65. Given that the atomic mass of copper from the periodic table is amu, which of the two isotopes is most abundant? Explain your answer.
Analyze the following chart and determine what elements are isotopes of the same element.
Atom A
Atom B
Atom C
Atom D #P 15 10 #N #E
Mass

23. Solutions
Copper has two isotopes: Cu-63 and Cu-65. Given that the atomic mass of copper from the periodic table is amu, which of the two isotopes is most abundant? Explain your answer.
The most abundant isotope is Cu-63 because it is closest to the mass of copper on the periodic table.
Analyze the following chart and determine what elements are isotopes of the same element.
Atom A
Atom B
Atom C
Atom D #P 15 10 #N #E
Mass 30 20 25

24. Average Atomic Mass
Check this out!!!

25. Calculating Atomic Mass
Isotope Mass Abundance
24Mg = amu x /100 = amu
25Mg = amu x /100 = amu
26Mg = amu x / = amu
Atomic mass (average mass) Mg = amu Mg
24.31
Basic Chemistry Copyright © 2011 Pearson Education, Inc.

26. Practice Activity
Gallium is an element found in lasers used in compact disc players. In a sample of gallium, there is 60.11% of 69Ga (atomic mass 68.93) atoms and 39.89% of 71Ga (atomic mass 70.92) atoms.
What is the atomic mass of gallium?
Basic Chemistry Copyright © 2011 Pearson Education, Inc.

27. Solution 69Ga 68.93 amu x 60.11 = 41.43 amu (from 69Ga) 100 71Ga
Atomic mass Ga = amu 31 Ga
69.72
Basic Chemistry Copyright © 2011 Pearson Education, Inc.

28. Radioactive Decay =

29. Half-Life
Half-life: Time it takes for an isotope to decay to its half amount.

30. Decay Curve

31. Drawing a Half-life Bar Graph
Draw a bar graph representing the decay of Barium-139 if you start with a 20 g sample and it must decay to less than 2 g. The half-life of Barium-139 is 80 minutes.
Bar Graph Representation
and Percent
Fraction Remaining Mass
Mass in Grams
Time passed (years)
# of Half-life

32. Drawing a Half-life Bar Graph Solutions
Graph Representation
and Percent
Fraction Remaining Mass
Mass in Grams
Time passed (years, min)
# of Half-life
50%
25%
100%
12.5%
6.25%

33. Drawing a Half-life Bar Graph Solutions
Graph Representation
and Percent
Fraction Remaining Mass
2/2
1/2
1/4
1/8
1/16
Mass in Grams
Time passed (years, min)
# of Half-life
50%
25%
100%
12.5%
6.25%

34. Drawing a Half-life Bar Graph Solutions
Graph Representation
and Percent
Fraction Remaining Mass
2/2
1/2
1/4
1/8
1/16
Mass in Grams
20 g
10 g
5 g
2.5 g
1.25 g
Time passed (years, min)
# of Half-life
50%
25%
100%
12.5%
6.25%

35. Drawing a Half-life Bar Graph Solutions
Graph Representation
and Percent
Fraction Remaining Mass
2/2
1/2
1/4
1/8
1/16
Mass in Grams
20 g
10 g
5 g
2.5 g
1.25 g
Time passed (years, min)
0 min
80 min
160 min
240 min
320 min
# of Half-life
50%
25%
100%
12.5%
6.25%

36. Drawing a Half-life Bar Graph Solutions
Graph Representation
and Percent
Fraction Remaining Mass
2/2
1/2
1/4
1/8
1/16
Mass in Grams
20 g
10 g
5 g
2.5 g
1.25 g
Time passed (years, min)
0 min
80 min
160 min
240 min
320 min
# of Half-life 1 2 3 4
50%
25%
100%
12.5%
6.25%

37. Harnessing the Nucleus
Nuclear Fission Nuclear Fusion
*Chain reaction *High temperatures/Sun & Star
*Huge amounts of energy produced *Greater energy produced
*Nuclear power plants *Less radioactive waste formed
*Impossible to create artificially

38. Final Reflection on Radiation……
* *