a solid is any substance
A which is hard
B which is three or more times denser than water
C whose atoms are held in a fixed arrangement with respect to each other
D found on a terrestrial planet
in the absence of excitation, electrons in an atom tend to be
A in any allowed orbit
B in the lowest allowed orbit
C in the nucleus
D not in the atom at all
the property of an atom which uniquely defines how it will behave chemical is
A the number of protons in the nucleus
B its physical size
C the number of neutrons in the nucleus
D its color
isotopes are
A rare compounds found only in isolated regions on Earth
B materials whose atoms are not as independent as those in a gas, but not as rigidly held in place as those in a solid
C atoms that have lost one or more electrons and, therefore, have a net electric charge
D atoms of a given element which have a fixed number of protons in the nucleus but varying
numbers of neutrons
the heaviest part of an atom is the
A orbits
B electrons
C nucleus
D light
in an undisturbed atom, all electrons are in
A random orbits
B the lowest orbit
C the lowest orbits with vacancies
D the nucleus
an electron in an atom will always try to
A go into the nucleus
B go to the smallest orbit that will fit into the atom
C go to the lowest allowed orbit which has a vacancy
D go to the emptiest orbit
an electron in an atom always tries to be
A in the nucleus
B in any orbit around the nucleus
C in the closest available orbit to the nucleus
D excited
electrons in an atom
A are the most massive particles
B are the largest particles
C carry a positive electric charge
D are restricted to only certain orbits around the nucleus
which of the following is true of all atoms?
A their protons, neutrons, and electrons all reside in the nucleus.
B their protons and electrons reside in the nucleus and the neutrons are in orbitals.
C their protons and neutrons are in the nucleus with electrons in orbitals.
D their protons, electrons, and neutrons are all in orbitals.
the number of electrons which can be in the same orbit is
A any number
B any number up to a specified maximum number
C two
D no choice
an atom in the ground state
A has lost its electrons
B can emit a photon
C is in its state of greatest energy
D can absorb a photon
when an atom is excited, then it has
A more electrons than protons.
B the same number of electrons as protons.
C one or more electrons stripped off.
D one or more electrons move up energy levels.
E seen a beautiful atom with an opposite charge.
when an electron bound in an atom makes a transition from any orbit to a smaller one it:
A absorbs energy.
B emits energy.
C can absorb or emit energy.
D neither absorbs nor emits energy.
the force which holds an electron in its orbit in an atom is
A nuclear
B magnetic
C electrical
D gravitational
in the energy-level model for the interaction of atoms and light, when an atom absorbs light at a specific wavelength,
A an electron drops down one energy level.
B the atom captures a free electron.
C an electron jumps up an energy level.
D the nucleus of the atom changes energy levels.
E nothing happens to the atom.
ionization of an atom occurs when
A the nucleus undergoes fission, or splitting
B an electron is removed from the atom
C an electron is lifted from the ground state to an excited level
D an electron is allowed to return to the ground state
the volume of space occupied by an atom, as defined by its electron orbits is thought to be
A entirely filled with matter
B like a raisin pudding
C mostly empty space
D none of these
an electron bound in an atom can have:
A any energy whatever.
B only specific energy values that are common to all atoms.
C only specific energy values that are common only to that specific kind of atom.
D only energies that are multiples of "c".
which of the following particles are not found in atomic nuclei
A neutrons
B electrons
C protons
D all of these particles occur in nuclei
each electron orbit in an atom
A must have at least one electron at all times
B must have at least one vacancy at all times
C cannot have more than one electron at any one time
D cannot have more than a certain number of electrons at any one time
the particles found in the nucleus of an atom are
A electrons and protons
B protons and neutrons
C electrons and neutrons
D electrons, neutrons and protons
which of the following quantities are quantized (have certain specified units)
A light
B electric charge
C orbits of electrons in atoms
D all of the above
the parameter of an atom which defines its chemical properties is
A its temperature
B its size
C the number of protons in the nucleus
D the total number of protons and neutrons in the nucleus
the orbits of electrons in atoms are
A the result of the force of gravity acting between the electron and the nucleus
B of a specified size
C of arbitrary size
D no longer considered a useful idea even in the most simple model of the atom
when an atom absorbs a light wave
A all electrons are removed from the atom
B some of the electrons combine with the nucleus
C an electron moves to a smaller orbit
D an electron moves to a larger orbit
electrons in an atom
A can only exist in certain, permitted orbits
B can only exist in the nucleus
C can exist in any orbit around the nucleus
D can exist anywhere within the atom, but are not moving
the smallest piece of an element which retains that element's chemical characteristics is
A an atom
B a proton
C an electron
D an erg
an atom is now known to consist of
A a small black hole with electrons held around it by intense gravitational force
B a uniform distribution of matter with electrons embedded within it
C a small, massive, electrically charged core with electrons surrounding it
D a crystalline structure of matter with electrons moving within it
a photon can boost an electron in an atom to a larger orbit if
A it has exactly the amount of energy required
B it is moving in the right direction
C it has the proper speed
D none of the above; photons are produced by electrons, not absorbed by them
as an atom's electron moves in a particular orbit, the atom
A constantly emits radiation as a result of the electron's motion
B does not emit radiation unless the electron jumps to a smaller orbit
C emits radiation of a particular energy, wavelength, and frequency which characterizes that particular orbit
D cannot absorb radiation (photons) unless the electron jumps into a smaller orbit
objects which carry like electric charges
A attract each other
B repel each other
C sometimes repeal and sometimes attract
D none of these
the particles that form the "nuclei" of atoms are
A protons and electrons
B protons and neutrons
C neutrons and electrons
D protons, neutrons, and electrons
if left alone, an atom will soon
A lose all its electrons
B lose all its neutrons
C have all its electrons in the smallest allowed orbits
D always have at least one excited electron
the physical force which holds an atom together is
A the electric force between nucleus and electrons
B the nuclear force from the protons and neutrons
C the gravitational force between nucleus and electrons
D the centrifugal force on the electrons, caused by their orbital motion
electron orbits in atoms
A only exist for short periods of time
B can be of any size or energy
C must be a specified size or energy
D are closely spaced around the nucleus
the physical structure of an atom is
A negatively charged electrons moving around a very small but massive central positively charged core
B positive and negative charged particles orbiting a small black hole
C negatively charged electrons mingling uniformly with positively charged protons in a small volume of space
D negatively charged electrons moving in a uniform volume of positively char matter
the majority of the mass of ordinary matter resides in
A the electrons and the nuclei, shared equally
B the nuclei of atoms
C the energy stored within the atom, in electromagnetic forces
D the electron cloud around the nuclei of atoms
which of the following is true of protons and electrons?
A both are charged but with charges of different signs and they have different masses.
B both are charged but with charges of different signs and they have the same masses.
C both are charged with charges of the same sign and they have different masses.
D their charges and masses are not precisely known but they are similar.
which of the following is generally true of "normal" atoms?
A they have more protons than electrons.
B they have fewer protons than electrons.
C they have the same number of protons and electrons.
D they have the same number of protons, electrons, and neutrons.
an atom may become excited by
A colliding with another atom.
B absorbing a photon.
C both of these.
D none of these.
in a normal atom, the electrons
A are located in the nucleus
B orbit about the nucleus
C collide frequently with the nucleus
D do not exist in the atom
one definition of a solid is
A it is hard
B it is a good conductor of electricity
C its atoms are held in place
D it is made of a single kind of atom or molecule
an atom of a certain element is defined by
A how many electrons orbit its nucleus
B how many protons are contained in its nucleus
C how many protons and neutrons are contained in its nucleus
D how large it is
in an energy level diagram, a forbidden transition is shown by
A an upward arrow
B a downward arrow that changes from one column to the next
C any arrow which changes by two or more columns
D no choice
the electron waves are
A invisible light waves
B real waves but different from light
C imaginary waves different from all other known waves
D the imaginary counterpart to light
when using an energy level diagram
A all electrons are shown
B only the outer electrons which are likely to make transitions are shown
C certain random electrons are shown
D no choice
quantum effects are not ordinarily experienced because they
A exist only in the mathematical imagination of physicists
B do not apply to the objects we use
C are too small
D have been proven incorrect
the Heisenberg uncertainty principle states that
A exact measurements are difficult to make
B an exact measurement of the position of an object is impossible
C an exact measurement of the velocity of an object is impossible
D simultaneous, exact measurements of both the position and velocity of an object are
impossible
compared to liquid water, molecules in ice are
A weakly held together
B rigidly held in a regular pattern
C moving rapidly
D very much closer together
the two quantities needed to specify an electric field vector are the strength of the force at some point and
A the speed of an electron at that point
B the direction of the force on an electron at that point
C the frequency of an electron at that point
D the strength of the vibrations of an electron at that point
the most important physical difference between a solid, liquid, and a gas is
A the temperature of the materials
B the density of the materials
C the volume occupied by the materials
D the relative strength of the forces acting between the atoms or molecules of the materials
the quantum hypothesis was proposed by
A Bohr
B Planck
C Kirchoff
D quantum
after two electrons have occupied the smallest orbit in an atom, additional electrons
A can still be placed in that orbit
B can only be placed on top of the original electrons
C must be placed in larger orbits
D cannot be added to the atom
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