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79 Cards in this Set
- Front
- Back
atomic mass unit
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a unit of mass that is exactly 1/12 the mass of a carbon-12 atom, or 1.660540 X 10^-27
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atomic number
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the number of protons in the nucleus of each atom of an element
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average atomic mass
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the weighted average of the atomic masses of the naturally occuring isotopes of an element
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Avogadro's number
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6.022 X 10^23; the number of particles in exactly one mole of a pure substance
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isotopes
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atoms of the same element that have different masses
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mass number
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the total number of protons and neutrons in te nucleus of an isotope
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molar mass
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the mass of one mole of a pure substance
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mole
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the amount of a substance that contains as many particles as there are atoms in exactly 12g of carbon-12
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nuclide
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the general term for any isotope of any element; another term for an atom that is identified by the numer of protons and neutrons in its nucleus
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law of conservation of mass
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mass is neither created nor destroyed during ordinary chemical or physical reactions
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law of definite proportion
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a chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the same or the source of the compound
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law of multiple proportions
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if two or more different compounds are composed of the same 2 elements. then the ratio of the masses of the 2nd element combined with a curtain mass of the first element is always a ratio of small whole numbers
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atom
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the smallest particle of an element that retains the chemical properties of that element
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nuclear forces
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these short-range proton-neutron, proton-proton, and neutron-neutron forces hold the nuclear particles together
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The word atom comes from a Greek word that means..
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unable to be divided
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The first person who suggested that matter was made up of atoms
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Democritus
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John Dalton's atomic theory
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atoms of the same element are exactly alike
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the nucleus of an atom has a ____ ________ charge
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positive electric charge
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where are neutrons and protons found
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in the nucleus of an atom
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atoms have equal numbers of
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protons and electrons
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according to modern atomic theory, the location of _____ is uncertain
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electron
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Isotopes of an element have the smame________ but different _____________
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atomic number, atomic mass
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an atom of potassium has an atomic mass of 39 amu and an atomic number of 19. ____ neutrons
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20
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an element's average atomic mass refers to the weighted average of the masses of all its naturally occuring
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isotopes
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the lightest hydrogen isoptope and most commonly occuring
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protium
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the Si unit used for counting small particles, such as atom
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mole
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what of one mol of a substance equals its molar mass
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the mass in grams
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the number of particles in one mole of a substnace
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avogadro's number
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in cathode ray tubes, the cathode rat is emitted from the negative electrode, called the ______
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cathode
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the smalles unit of an elemnt that can exist either alone of in combination with atoms of the same or different elements
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atom
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a positively charged particle found in the nucleus is called
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proton
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a nuclear particle that has no elextrical charge is called a
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neutron
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the subatomic particles that are least massive and most massive, respectively, are the
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electron and neutron
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the amount of substance that containst the same number of atoms as 12g of carbon-12
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mole
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an atoms atomic numer is equal to
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its number of protons
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an toms mass number is determined by
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adding its protons and neutrons
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two atoms that have the same number of protons but different numbers of neturons are called
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isotopes
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Avogadros number states that one mole of a pure substance contains
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6.022X 10^23 atoms
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first suggested the idea of atoms
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Democritus
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Identified the electron
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thomson
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calculate dmass of electron
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millikan
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discovered the nucleus
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rutherford
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discovered proton
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rutherford
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discovered neutron
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chadwick
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electron-- symbol, location, and electrical charge
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e- surrounding are of nucleus, negative
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neutron- symbol, loc, and charge
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n^o nucleus, neutral
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proton - symbol, loc, and charge
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p^+ nucleus, positive
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thomson model
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plum pudding, nucleus outside
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dalton model
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big black circle
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rutherford
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circle and inside it has surounding electrons, positive nucleus with 3 plus's
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the number of neutrons in an atom is reffered to as its atomic number (T F)
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F- number of protons
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the periodic table is arranged by increasing atomic number
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T
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Atomic number is equal to the number of electrons in the atom
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F- numer of protons
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The numer of protons in an atom identifies it as an atom of a particular element
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T
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Most atoms have either a positive or a negative charge
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F
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the mass of an electron is
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smaller than the mass of a proton, smaller than the mass of a neutron, a tiny fraction of the mass of an atom
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one atomic mass unit is
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1/12 the mass of a carbon-12 atom
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the atomic mass of an atom is usually not a whole number because it accounts for
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both the relative abundance and the mass of each of the atom's isotopes
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the atomic number of oxgen ,8,indicates that there are eight
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protons in the nucleus of an oxygen atom
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the number that is the total number of protons and neutrons in the nucleus of an atom is the
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mass number
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isotopes of a particular element differ in
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the number of neutrons in the nucleus
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in determing atomic mass units, the standard is an
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C-12 atoms
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the chemical shorthand for atomic mass units
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amu
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the average atomic mass of an element is the weighted average of atomic masses of the
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naturally occurring isotopes
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because isotopes have differnt masses, they differ in their chemical behavior
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FALSE
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the mass number and the relative atomic mass of a given nuclide are close in value
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true
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the percentage of each isotope in the naturally occurring element differs in various places on Earth
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false
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the average atomic mass of an element depends on bothe mass and abundance of each element's isotopes
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true
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the elements on the periodic table of elements are listed in the order of atomic number
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true
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schoolteacher who studied atoms and proposed an atomic theory
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john dalton
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according to Dalton's atomic theory, atoms
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of a particular element are identical in size, mass, and other properties
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one part of Daltons atomic theory that has been modified is the idea that
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atoms cannot be subdivided
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daltons atomic theory did not explain
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conservation of energy
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the law of definite composition
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was explained by Dalton's atomic theory
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the fact that lead forms two oxides of different formulas, PbO and Pb0 ^2 is an example of the
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law of multiple proportions
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the center of an aotm contains positively charged ________ as well as neutral particles called __________
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protons, neutrons
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surrounding the center of the atom is a region occupied by electrons. electrona re
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identical negatively charged particles
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the paddle wheel experiment shows that
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the cathode ray has enough mass to perform work
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Rutherford's model of the atom suggests that
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an atom has a great deal of empty space
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