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79 Cards in this Set

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