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Nuclear Reactions. -. -. -. +. +. +. +. +. +. -. -. -. Elementary Particles. The only atomic particles that play a part in nuclear reactions are the protons and the neutrons; electrons do not play a part in nuclear reactions.
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- - - + + + + + + - - - Elementary Particles • The only atomic particles that play a part in nuclear reactions are the protons and the neutrons; electrons do not play a part in nuclear reactions. • We use the following notation to describe the specific element we are considering in a nuclear reaction. • X represents the element, Z represents the atomic number (number of protons), and A represents the atomic mass number (the number of protons and neutrons) of the element.
Isotopes • For the nuclides below, determine the number of neutrons and protons.
Atomic Radii • Use the formula below in order to find the atomic radii of the following Nuclide.
Particle Masses • Nuclear masses are specified in unified atomic mass units or amu • The atomic mass of a neutron is 1.008665 u. • The atomic mass of a proton is 1.007276 u. • A neutral hydrogen atom , which has an electron and a proton but no neutron, has a mass of 1.007825 u. • We will use the mass of a neutral hydrogen in the place of the mass of a proton. • The mass of a nucleus is known to be 4.002602 u. • Compare this mass to the masses of the appropriate number of protons and neutrons combined. • What did you discover? • In the question above, you found that the actual mass was less than the mass of its constituent parts. • What do you think happened to the “missing mass?”
Binding Energy • The difference in masses discovered on the previous slide is known as the total binding energy of the nucleus. • This energy represents the amount of energy that must be put into the nucleus in order to break apart its protons and neutrons. • For a given nucleon , the total binding energy, Eb, is • Find the amount of energy put into the following nuclide in order to break it apart.
Nuclides • This notation is very important because it allows us to represent different isotopes of an element X. • For a given atom, carbon for instance, nuclei are found that contain different numbers of neutrons even though they contain the same amount of protons. • Here are the symbols of some different isotopes of carbon. • They are all Carbon because they all have 6 protons; however, they have different numbers of neutrons. • These “different” carbons are known as Isotopes of each other. • The carbon to the left is known as “Carbon 12” because it has six neutrons and six protons. • The carbon to the right is known as “Carbon 16” and has six protons and ten neutrons.
Alpha Decay • Alpha decay is one of several types of nuclear decay. • In alpha decay a parent nucleus is broken apart to yield a daughter nucleus and an alpha particle. • The general equation for alpha decay is as follows. • An alpha particle is a neutral helium atom. Daughter Parent Alpha
Q-Value • In alpha decay, the masses of the daughter nucleus and alpha particle combined are less than the mass of the parent nucleus. • The “missing mass” is converted into the kinetic energy of the alpha particle and the daughter nucleus. • This “missing mass” or released energy is known as the disintegration energy. • It is also known as the Q-value for the particular parent nucleus. • The equation used to determine the Q-value is • Find the daughter nuclide due to alpha decay and the Q-values or the nuclides below.
Beta Minus Decay • In Beta decay a parent nucleus is broken apart to yield a daughter nucleus and a Beta particle. • A Beta particle is either an electron (e-) or a positron (e+). • If an electron (also known as a -) is emitted during the decay process, then the decay process is known as a “Beta minus decay.” • The general equation for beta minus decay is as follows. • The underlying reaction is the conversion of a neutron into a proton, electron, and an anti-neutrino. Neutron Proton
0 KEmax Beta Minus Decay • Calculate the KE for Beta Minus decay for
Neutron Proton Beta Plus Decay • If a Positron (also known as a +) is emitted during the decay process, then the decay process is known as a “Beta plus decay.” • The general equation for beta plus decay is as follows. • The underlying reaction is the conversion of a proton into a neutron, positron, and a neutrino.
0 KEmax Beta Plus Decay • Calculate the KE for Beta Minus decay for
Electron Capture • In electron capture, an orbital electron is captured by the nucleus, combines with a proton, and forms a neutron and a neutrino. • The general equation for electron capture is as follows. • The underlying equation for electron capture is the conversion of a proton and an electron into a neutron and a neutrino. Neutron Proton