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92 Cards in this Set
- Front
- Back
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Atomic nuclei are made of these two things
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Protons
neutrons |
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What are protons and neutrons called collectively?
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Nucleons
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In nuclear chemistry what is an atom referred to as?
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A nuclide
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How is an atom identified in nuclear chemistry?
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By the number of protons and neutrons in its nucleus.
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Simple, What is an atom made up of?
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Protons,neutrons, and electrons
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Because an atom is made of prtons,neutrons,and electrons you might expect this mistakenly?
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That the mass of an atom be the same as the mass of an equal number of isolated, protons,neutrons, and electrons.However this is not the case
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Mass defect is ...
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The difference between the mass of an atom and the sum of the masses of its protons, neutrons, and electrons.
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Albert Einstein's equation of E=Mc˛ answers this question
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What causes the lost in mass?
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According to Albert Einstein's equation mass can be...
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Mass can be converted to enerygy and energy to mass.
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The mass defect is caused by...
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The conversion of mass to energy upon the formation of the nucleus.
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Nuclear binding energy is...
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The energy released when a nucleus is formed from nucleons.
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Nuclear binding energy can also be thought of as energy required to do this...
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The amount of energy required to break apart the nucleus.
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Therefore, the nuclear binding energy is also a measure of the _______ of a nucleus.
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Stability
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This is used to compare the stability of different nuclides.
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The binding energy.
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The binding energy per nucleon is...
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The binding energy of the nucleus divided by the number of nucleons it contains.
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The higher the binding energy per nucleon then...
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The more tightly the nucleons are held together.
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Elements with intermediate atomic masses have...
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The greatest binding energies per nucleon and are therefore the most stable.
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Stable nuclides have_____ characteristics...
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Certain characteristics.
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A beltlike graph is obtained when...
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When the number of protons in stable nuclei is plotted against the number of neutrons
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The band of stability is...
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When the stable nuclei cluster over a range of neutron-proton ratios
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Among atoms having low atomic numbers, the most stable nuclei are those with a neutron-proton ratio of approximately this
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1:1 are the most stable
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Protons in a nucleus repel...
but.... |
All other protons through electrostatic repulsion
but the short range of nuclear forse allows them to attract only protons very close to them. |
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As the number of protons in a nucleus increases, the electrostatic force between the protons in the nucleus also ______ faster than the this _______ and do this to the nucleus.
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Increases
nuclear force stabilizes the nucleus |
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83 is this on the periodic table
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Bismuth
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Stable nuclei tend to have this types of numbers of nucleons.
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Even numbers of nucleons.
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Out of the 256 stable nuclides ____ have even numbers of protons and neutrons.
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159
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The stability of a nucleus is greatest when the nucleons-like electrons- are ______.
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Paired
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According to the nuclear shell model....
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Nucleons exist in different energy levels or shells in the nucleus.
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The numbers of nucleons tht represent completed nuclear energy levels are called....
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magic numbers
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Unstable nuclei undergo _____ change that change their number of _____ and ___.
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Spontaneous change
Protons and neutrons |
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In the process of this spontaneous change, unstable nuclei give off _____ amounts of energy and ____ their stability.
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large amounts of energy
increase their stability |
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A nuclear reaction is....
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A reaction that affects the nucleus of an atom.
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In equations representing nuclear reactions, the total amounf of atomic numbers must be equal to _______ on both sides of the equation.
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total of the atomic numbers=the total of the mass numbers
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The identity of an element changes when...
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The atomic number changes
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A transmutation is ...
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A change in the identity of a nucleus as a result of a change in the number of its protons.
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Radioactive decay was first discovered by...
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Henri Becquerel
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Radioactive decay is...
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The spontaneous disintegration of a nucleus into a slightly lighter nucleus,accompained by emission of particles,electromagnetic radiation, or both.
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What is nuclear radiation...
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Particles or electromagnetic radiation emitted from the nucleus during radioactive decay.
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Uranium is a ______ nuclide.
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Radioactive
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Radioactive nuclide is ....
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An unstable nucleus that undergoes radioactive decay.
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They disovered two new radioactive elements...
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The Curies
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The two new elements that the Curies discovered were _____ and _____
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Polonium and radium
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Thorium is _______
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Radioactive
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All nuclides beyond atomic number 83 are .....
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unstable and radioactive
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A nuclide's type and rate of decay depend on the _____ content and the ______ level of the nucleus.
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The nucleon content and the energy level of the nucleus.
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An alapha particle is....
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Two protons and two neutrons bound together and is emitted from the nucleus during some kinds of radioactive decay.
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A beta particle is ...
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An electron emitted from the nucleus during some kinds of radioactive decay.
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Elements above the band of stability are unstable because they have too many...
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neutrons
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To decrease the number of neutrons, a neutron can be converted into a _____ or a ______
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Into a proton or an electron
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Elements below the band of stability have too many _____ to be stable
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Too many protons
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In electron capture...
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An inner orbital electron is captured by the nucleus of its own atom.
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According to the nuclear shell model, gamma rays are produced when...
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Nuclear particles undergo transitions in nuclear -energy levels.
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No two radioactive isotopes decay at what...
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The same rate
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Half life is...
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The time required for half the atoms of a radioactive nuclide to decay.
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More stable nuclides decay _____ and have ______ half-lives
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more slowly and have longer half-lives
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Less-stable nuclides decay very _____ and have _______ half lives
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quickly and have shorter half lives
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True/False one nuclear reaction is not always enough to produce a stable nuclide?
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True may need more
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A decay series is...
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A series of radioactive nuclides produced by successive radioactive decay until a stable nuclide is reached.
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The heaviest nuclide of each decay series is the...
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parent nuclide
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The nuclides produced by the decay of the parent nuclides are called....
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daugther nuclides
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Alll naturally occurring nuclides with atomic numbers greater than 83 belong to ____ of 3 natural decay series.
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1
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The parent nuclides are these three...
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Uranium-238
Uranium-235 Uranium-332 |
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Artificial radioactive nuclides are ...
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Radioactive nuclides not found naturally on Earth.
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Artifical radioactive nuclides are made by...
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Artifical transmutations
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Artificial transmutations are...
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Bombardment of stable nuclei with charged and uncharged particles.
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These can easily penetrate the nucleus...
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Neutrons
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Positively charges alpha particles,protons,and other ions are _______ by the nucleus.
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Repelled
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Radioactive isotopes of all natural elements have been produced by this process...
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artificial transmutation
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Transuranium elements are...
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Elements with more than 92 protons in their nuclei
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Transuranium elements are...
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Elements with more than 92 protons in their nuclei.
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Nuclear radiation included these three things...
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alpha particles
beta particles gamma rays |
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These rays have the greatest penetrating abilities...
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gamma rays
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The roentgen is...
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A unit used to measure nuclear radiation
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Ionization can ______ liviing tissue
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Damage
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Radiation damage to human tissue is measured in ...
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rems
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One rem is the quantity of ionizing radiation that does as much damage to human tissue as...
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As done by 1 roentgen of high-voltage X rays.
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Average enviromental background radiation exposure for people in the US is about...
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0.1 rem per year
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The maxium amount of radiation exposure is ...
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0.5 rem
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Every radioactive substance has a ....
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half life
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In nuclear fission...
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A very heavy nucleus splits into more-stable nuclei of intermediate mass.
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Missing mass converted into...
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Energy
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When uranium-235 is bombarded with slow neutrons it is made _____
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unstable
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What does rem stand for...
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Roentgen equivalent man
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A chain reaction is...
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A reaction in which the material that starts the reaction is also one of the products and can start another reaction.
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Critical mass is...
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The minimum amount of nuclide that provides the number of neutrons needed to sustain a chain reaction.
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Fission was 1st named by...
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Lise Meitner
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Fission is ....
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The spillting of a heavy nucleus and releases tons of energy
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Fusion is...
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The joining of light nucli to join into one heavy nucleus
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Radioactive decay was 1st discovered by him using Uranium.
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Henri Becquerel
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Beyond atomic number 83 on the periodic table the repulisive force of this is so great that...
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No stable nuclides exist
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The most stable nuclides are those having __,__,__,___,__ as # of protons or # of neutrons or their sum.
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2,8,20,28,50,82,or 126
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Only _____ nuclides have odd numbers of both protons and neutrons.
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4
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