By: Joy Mihanni And Jonathan Samuels Radiation PowerPoint By: Joy Mihanni And Jonathan Samuels

Outline In this presentation, you will learn about: Alpha Emission Beta Emission Positron Emission Electron Capture Gama Emission Conclusions Bibliography

Alpha Emission The reason alpha decay occurs is because the nucleus has too many protons which causes an excessive repulsion. A radioactive nucleus that undergoes alpha emission emits a helium nucleus, 42He. The remaining nucleus has two fewer protons and two fewer neutrons. The atomic number declines by two and the mass number by four.

Beta Emission A radioactive nucleus that undergoes beta emission has a neutron in its nucleus that converts into a proton and an electron, then it ejects the electron. The remaining nucleus has one more proton and one fewer neutron. The atomic number increases by one and the mass number stays the same.

Positron Emission A radioactive nucleus that undergoes positron emission has a proton in its nucleus that converts into a neutron and a positron, then it ejects the positron. A positron is an anti-electron: it has the same mass, but has a +1 change instead of a -1 charge. The remaining nucleus has one less proton and one more neutron: the atomic number decreases by one and the mass number stays the same.

Electron Capture Electron capture is one process that unstable atoms can use to become more stable. During electron capture, an electron in an atom's inner shell is drawn into the nucleus where it combines with a proton, forming a neutron and a neutrino. The neutrino is ejected from the atom's nucleus. Since an atom loses a proton during electron capture, it changes from one element to another. Although the numbers of protons and neutrons in an atom's nucleus change during electron capture, the total number of particles (protons + neutrons) remains the same.

Gamma Emission A radioactive nucleus that undergoes gamma emission emits a very high energy photon. (Gamma ray) This is due to the nucleus reorganizing itself in a lower energy state, much like a photon is given off by an electron when it moves from a high energy level to a lower one. The nucleus does not change.

Conclusions In conclusion, if a nucleus has some sort of a flaw then it is considered unstable. That flaw may be the wrong combination of protons and neutrons, or it may be a problem with the level of energy. Whatever the flaw, if it is severe enough, the nucleus will try to correct the problem. This process of correcting the problem is known as radioactive decay. Radiation is energy in the form of waves. Alpha, Beta, and Gamma emissions all deal with the break down of a nucleus. Electron capture, captures a particle rather than emitting it, and the combines with a proton.

Bibliography Gagnon, Steve. "Electron Capture." Jefferson Lab. 27 Oct. 2007. Perdue University. 28 Oct. 2007 <http://education.jlab.org/glossary/electroncapture.ht ml>. "Nuclear Chemistry Index." Cartage. 2006. Virginia Tech Department of Chemistry. 27 Oct. 2007 <http://www.cartage.org.lb/en/themes/sciences/chemi stry/NuclearChemistry/NuclChemIndex/mainpage.ht m>. Nave, Carl R. "Radioactivity." Hyperphysics. 2006. Georgia State University. 28 Oct. 2007 <http://hyperphysics.phy- astr.gsu.edu/hbase/nuclear/radact2.html>.