Unit 17 Radioactivity Atomic mass is the average
- Slides: 49
Unit 17 Radioactivity
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 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
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 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 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 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 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 Geiger Counter works
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 = 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
Drawing of the condition of Chernobyl reactor after the melt down
Chernobyl reactor after the melt down
Chernobyl reactor core
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
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
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 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
http: //en. wikipedia. org/wiki/File: Teller-Ulam_device. png
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. Crystallization 34. Becquerel 40. Rutherford 45. Electroscope
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 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 . .
- Is atomic mass and relative atomic mass the same
- Atomic weight of oxygen
- Atomic
- Atomic mass formula
- How to calculate average atomic mass
- Atomic mass of boron 10
- Average atomic mass def
- Mass number of lead
- Atomic mass average calculator
- Average atomic mass of chlorine
- Carbon-12 atomic number
- Mass gram
- Atomic mass vs molar mass
- Amu vs molar mass
- Define atomic mass unit
- Carbon amu
- Chemical equation
- Atomic mass unit
- Atomic mass unit
- Trends periodic table
- Periodic trends atomic radius
- Atomic number vs atomic radius
- Natural and artificial radioactivity
- Natural vs artificial radioactivity
- Becquerel discovery of radioactivity
- Who discovered radioactivity
- Who discovered uranium
- Natural and artificial radioactivity
- Radioactive decay law
- Radioactivity as spontaneous disintegration
- Mta
- Radioactivity
- Unconformity
- Datación radiométrica
- Natural radioactivity
- Environmental radioactivity
- Natural radioactivity
- Radioactivity phenomenon
- Key terms radioactivity and nuclear reactions
- Units of radioactivity
- Radioactive formula
- Defination of radioactivity
- Defination of radioactivity
- Defination of radioactivity
- Alpha particle in electric field
- Motion in a straight line
- Period 5 transition element 51 neutrons
- Atomic mass trend
- Drawing atoms practice
- How to find empirical formula with percentages