Download presentation
Presentation is loading. Please wait.
Published byDina Arnold Modified over 9 years ago
1
Nuclear Energy
2
Nuclear energy is all around us and can be used for medical purposes. Nuclear energy is when an atom is split and releases energy or particles.
3
Nuclear Energy To fully understand Nuclear Energy we need to take a look at how an atom can split. 1 way this can happen is called Radioactive Decay.
4
Radioactive Decay Isotopes with unstable nuclei emit particles and/or energy to become stable isotopes. Any time an unstable nucleus emits particles the number of protons and neutrons changes. The energy released is called nuclear radiation.
5
Nuclear Radiation There are 4 types of nuclear radiation.
6
Alpha particles Alpha particles are actually 2 protons and 2 neutrons. The same as a helium nucleus. They are represented by 4 2 He Alpha particles are positively charged and massive.
7
Beta Particles Beta particles are fast moving particles, usually electrons. Because electrons are almost mass less and have a negative charge we represent Beta particles as: 0 -1 e
8
Positrons Once in a while the Beta particle given off changes its charge to positive. This now mass less tiny positive charge is called a Positron. It’s represented by: 0 +1 e
9
Gamma Rays Gamma rays are not matter they are a form of electromagnetic energy. They are small packets of energy called photons. Although they have no charge, they can excite atoms and cause chemical reactions.
10
Neutrons Neutron emission is when the atom looses a neutron. It is the hardest to decay to stop. Neutrons do not have a charge, so the particles are able to travel through most materials with out ionizing the material. It’s represented by: 1 0 n
11
Nuclear Decay and Equations Nuclear Decay equations are like chemical reaction equations. The nucleus before emitting a particle is the reactant. The particle emitted and the resulting new isotope are the products.
12
Nuclear Decay Equations When an isotope goes through Beta Decay the mass number stays the same, but the atomic number increases by 1. 14 6 C 14 7 N + 0 -1 e During Beta decay an electron is given off and a Neutron changes into a proton.
13
Nuclear Decay and Equations When an Isotope goes through Alpha Decay both the mass number and the atomic number change. 226 88 Ra 222 86 Rn + 4 2 He The reactant has lost 2 protons and 2 neutrons.
14
Decay Rates The time it takes for half of a radioactive isotope to decay is called a half-life.
15
Calculating Half Life We can use the known half life of each element to help us figure out how much of a substance remains. Example: Radium 226 has a half life of 1599 years. How long will 7/8ths of a sample take to decay.
16
Step 1: Figure out how much is left of the sample at the end of the decay period. 1 – 7/8 = 1/8
17
Radium 226 has a half life of 1599 years. How long will 7/8ths of a sample take to decay. Step 2: Figure out how many half lives it takes to get to the sample down to the remaining. ½ x ½ x ½ = 1/8
18
Radium 226 has a half life of 1599 years. How long will 7/8ths of a sample take to decay. Step 3: Count the number of half lives and multiply that by the time it takes for one half life. 3 half lives x 1599yrs = 4797 years
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.