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15 Cards in this Set
- Front
- Back
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What does the Law of Conservation of Mass say?
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Mass is neither created nor destroyed in a chemical reaction or physical change
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What does the Law of Definite Proportions say?
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Every chemical compound is made up of elements in a definite ration by mass.
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What does the Law of Multiples Proportions say?
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When two or more compounds are formed from the same elements, the ration of masses of each element in the compounds for a given mass of any other element is a small whole number.
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What is the atomic mass unit
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1 amu=1.66*10^(-24) g (based on carbon 12 ; 12C is defined to have a mass unit of exactly 12 amu)
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When is an element electrically neutral?
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When the number of electrons (e-) and protons (p+) are equal.
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What is an isotope?
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An isotope is an atom which has the same number of protons (hence electrons) but a different number of neutrons.
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What is the atomic mass of an element?
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The atomic mass is the weighted average of the masses of the individual isotopes of the element.
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What is the weighted average?
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It is the sum of the masses times its fraction present.
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In the periodic table, what are groups and periods?
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Groups are columns of the table . Periods are rows of the table.
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What is the formula that gives the maximum number of electrons that can be present in a shell n?
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maximum number in shell n = 2n^2
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What is the maximum number of electrons that can exist in the valence shell?
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8
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An electron in the orbit closest to the nucleus has the __. That electron is said to be in its__
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lowest energy....ground state
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An electron might be able to move to an orbit of higher energy if the atom __
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absorbed a discrete quantity of energy.
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An electron in a excited state will return to a lower energy level with__. This is called a __
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a release of energy in the form of light (photon)...quanta.
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Each orbit of an atom corresponds to__
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a definite energy level.
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