Unit 17 Radioactivity Atomic mass is the average

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Unit 17 Radioactivity

Unit 17 Radioactivity

Atomic mass is the average number of p+ and n found in the nucleus.

Atomic mass is the average number of p+ and n found in the nucleus. Carbon 12. 0111 6 C All elements have Isotopes. Atoms of the same element with a different number of neutrons found in the nucleus, therefore they have different masses. Chemical symbol: 1 or 2 letters used to represent an element. The 1 st letter is always capital. If there is a 2 nd letter, it is lower case. Atomic number is the number of p+ found in the nucleus.

Subatomic Particles Particle Mass Charge Location in the atom Proton (p+) 1 amu +1

Subatomic Particles Particle Mass Charge Location in the atom Proton (p+) 1 amu +1 Nucleus 1. 673 x 10 -24 g 1. 602 x 10 -19 C 1 amu 0 Nucleus -1 Revolving around nucleus Neutron (n) Electron (e -) (center of atom) 1. 675 x 10 -24 g 1/ 1837 amu 9. 109 x 10 -28 g -1. 602 x 10 -19 C

Structure of the Atom Protons & Neutrons

Structure of the Atom Protons & Neutrons

Radioactivity 1. 2. 3. All naturally occurring elements with atomic numbers greater than 83

Radioactivity 1. 2. 3. All naturally occurring elements with atomic numbers greater than 83 are radioactive. Uranium is the largest naturally occurring element. Every element above 92 is man-made. Radioactivity is the uncontrollable decay of an atomic nucleus with the emission of particles and rays, with a lighter element formed. Radioactive elements can affect photographic plates, ionize gases, and cause physical effects (mutations).

4. Half-life is the TIME it takes for ½ of the radioactive atoms to

4. Half-life is the TIME it takes for ½ of the radioactive atoms to decay. Different elements take a different amount of time for a half-life to occur. U Th half-life takes 4. 5 billion years Po Pb half-life takes 1. 6 x 10 -4 seconds

1 line = 5 atoms Go from 0 to 120 atoms Radioactive Decay curve

1 line = 5 atoms Go from 0 to 120 atoms Radioactive Decay curve U Th Pb Atoms remaining Po Time (rolls) 1 line = (depends of class data) Go from 0 rolls to ____ rolls

Remember that half-life is the period of time required for half of the atoms

Remember that half-life is the period of time required for half of the atoms to go through decay. For a single element, each half – life is the same amount of time. So, if it takes 2 minutes for element X to go through one half – life, it takes 4 minutes to go through 2 half – lives. During each half – life, half of the atoms go through decay. remaining 1 g ½g 1 st half-life decayed ½g ¼g 2 nd 1/ 8 g 3 rd ¾g 7/ 8 g

Radioactive Emissions o o o Alpha particle a = Helium nucleus easily stopped Beta

Radioactive Emissions o o o Alpha particle a = Helium nucleus easily stopped Beta particle b = electron emoderately difficult to stop Gamma ray g = pure energy very difficult to stop 4 2 He

a or b Radioactive emission causes ionization of Ar gas, completing circuit, clicks! How

a or b Radioactive emission causes ionization of Ar gas, completing circuit, clicks! How a Geiger Counter works

Radioactivity (clicks/min) Radioactivity verses Distance 1 line = depends on class data Go from

Radioactivity (clicks/min) Radioactivity verses Distance 1 line = depends on class data Go from 0 to ____ Distance (in) 1 line = 1 inch Go from 0 to 12 inches

min Effectiveness of Various Barriers to Radioactivity clicks/ Card board Radioactivity Al 1 line

min Effectiveness of Various Barriers to Radioactivity clicks/ Card board Radioactivity Al 1 line = depends on class data Go from 0 to ? Pb Number of barriers 1 line = 1 barrier Go from 0 to 10 barriers

Typical nuclear reactor

Typical nuclear reactor

Drawing of the condition of Chernobyl reactor after the melt down

Drawing of the condition of Chernobyl reactor after the melt down

Chernobyl reactor after the melt down

Chernobyl reactor after the melt down

Chernobyl reactor core

Chernobyl reactor core

New structure that will enclose the destroyed reactor at Chernobyl. 500 feet long, 840

New structure that will enclose the destroyed reactor at Chernobyl. 500 feet long, 840 feet wide, and taller than the Statue of Liberty.

Fukushima Daiichi Power Plant Japan

Fukushima Daiichi Power Plant Japan

Nuclear Notation Atomic mass X A Atomic number z Element symbol Kinds of Decay

Nuclear Notation Atomic mass X A Atomic number z Element symbol Kinds of Decay a A A-4 N + 4 He Alpha decay a Z X Z-2 2 N = new element A N + e X Z+1 Beta decay b AZ b N p+ + e-

a b 241 Pu 94 a b a a b

a b 241 Pu 94 a b a a b

Calculating half-life of Ba 56 137 Radioactivity (clicks/min) To calculate the half-life from data,

Calculating half-life of Ba 56 137 Radioactivity (clicks/min) To calculate the half-life from data, determine the time when exactly half of the radioactive atoms remain. Time (sec)

g Ba 137 Ba 56 137 56 Radioactive Decay of Ba to determine the

g Ba 137 Ba 56 137 56 Radioactive Decay of Ba to determine the half - life Time (s) (clicks/min) 0 30 60 90 120 150 180 210 240 270 25, 000 23, 000 20, 500 18, 500 16, 800 15, 200 13, 800 12, 750 11, 500 10, 300 330 360 390 420 450 480 510 540 9, 400 8, 700 7, 800 7, 000 6, 200 5, 600 5, 050 4, 650 4, 200

Bikini island

Bikini island

http: //en. wikipedia. org/wiki/File: Teller-Ulam_device. png

http: //en. wikipedia. org/wiki/File: Teller-Ulam_device. png

Review 1. 2. 3. 4. 5. a a a. 226 Ra 222 Rn 218

Review 1. 2. 3. 4. 5. a a a. 226 Ra 222 Rn 218 Po 88 86 84 b b b. 214 Bi 214 Po 214 At Top # = proton + neutron (atomic mass) Bottom # = protons (atomic number) 83 84 85 Protons and neutrons are located in the nucleus, with the electrons located in energy levels around the nucleus. Alpha a particle is a helium nucleus Beta b particle is an electron Gamma g ray is pure energy 1/8 pound remaining 7/8 pound decayed A device used to detect radiation by counting the number of emissions per unit of time

Nuclear chemistry Crossword Down 27. Cyclotron 28. Spectrograph 39. Meson Across 16. Emanations 18.

Nuclear chemistry Crossword Down 27. Cyclotron 28. Spectrograph 39. Meson Across 16. Emanations 18. Crystallization 34. Becquerel 40. Rutherford 45. Electroscope

Size: 468 × 454 Type: 39 KB JPG Mushroom Cloud from a nuclear bomb.

Size: 468 × 454 Type: 39 KB JPG Mushroom Cloud from a nuclear bomb.

Bikini Atoll is a circle of island with a deep central lagoon. From 1946

Bikini Atoll is a circle of island with a deep central lagoon. From 1946 to 1958 the US exploded 23 nuclear bombs to analyze what happens. All of the local people were relocated to another atoll before the explosions

Light Bright Assignment 1 H 2 H 3 H . .

Light Bright Assignment 1 H 2 H 3 H . .