CLEP CHEMISTRY EXAM
John Dalton - ANSWER- Proposed that matter is composed of atoms;
these atoms have different identities called elements, which combine to
form compounds; measured masses of reactants and products.
J.J. Thompson - ANSWER- Observed deflection of particles in a
cathode ray tube; proposed that atoms are composed of positive and
negative charges; developed the plum pudding model of the atom
Robert Millikan - ANSWER- Calculated the charge-to-mass ratio of
electrons using oil drops falling in an electric field; surmised the charge
of a single electron
Ernest Rutherford - ANSWER- Used the deflection of alpha particles in
a cathode ray tube to discover that most of the atom is empty space, with
protons and neutrons centered in the nucleus.
,Niels Bohr - ANSWER- Determined that electrons exist around the
nucleus at a fixed radius; electrons with higher energy exist farther from
the nucleus. Electrons give off electromagnetic radiation when moving
between energy levels.
Max Planck - ANSWER- Determined that energy is quantized, or
composed of discrete bundles.
6.63 x 10^-34 J*sec - ANSWER- Planck's Constant (h)
3.00 x 10^8 m/sec - ANSWER- Speed of Light (c)
E = hv - ANSWER- Energy of a Photon Formula (1)
E = hc / wavelength - ANSWER- Energy of a Photon Formula (2)
Louis DeBroglie - ANSWER- Combined Einstein's relationship between
mass and energy and the relationship between velocity and the
wavelength of light. All particles with momentum have a corresponding
wave nature.
Wavelength = h / mv - ANSWER- Wavelength of Particles Formula
, Heisenberg's Uncertainty Principle - ANSWER- It is impossible to
simultaneously know the position and momentum of an electron.
Erwin Schrodinger - ANSWER- Attributed a wave function to electrons,
describing the probability of where an electron might exist.
Orbitals - ANSWER- Regions of high probability where electrons might
exist; broken into four levels: s, p, d, or f
Atomic Mass - ANSWER- The cumulative mass of all the particles in
the atom; found by adding the masses of the protons and neutrons.
Units: Atomic Mass Units (AMU)
Example:
helium = 2 protons + 2 neutrons
= 4 AMU
Atomic Number - ANSWER- The number of protons in the nucleus of
an atom, or the total nuclear charge. Also the number of electrons
surrounding the nucleus.
Isotopes - ANSWER- Atoms with the same number of protons but
different numbers of neutrons.
Example: carbon-12 (6 neutrons) vs carbon-14 (8 neutrons)
John Dalton - ANSWER- Proposed that matter is composed of atoms;
these atoms have different identities called elements, which combine to
form compounds; measured masses of reactants and products.
J.J. Thompson - ANSWER- Observed deflection of particles in a
cathode ray tube; proposed that atoms are composed of positive and
negative charges; developed the plum pudding model of the atom
Robert Millikan - ANSWER- Calculated the charge-to-mass ratio of
electrons using oil drops falling in an electric field; surmised the charge
of a single electron
Ernest Rutherford - ANSWER- Used the deflection of alpha particles in
a cathode ray tube to discover that most of the atom is empty space, with
protons and neutrons centered in the nucleus.
,Niels Bohr - ANSWER- Determined that electrons exist around the
nucleus at a fixed radius; electrons with higher energy exist farther from
the nucleus. Electrons give off electromagnetic radiation when moving
between energy levels.
Max Planck - ANSWER- Determined that energy is quantized, or
composed of discrete bundles.
6.63 x 10^-34 J*sec - ANSWER- Planck's Constant (h)
3.00 x 10^8 m/sec - ANSWER- Speed of Light (c)
E = hv - ANSWER- Energy of a Photon Formula (1)
E = hc / wavelength - ANSWER- Energy of a Photon Formula (2)
Louis DeBroglie - ANSWER- Combined Einstein's relationship between
mass and energy and the relationship between velocity and the
wavelength of light. All particles with momentum have a corresponding
wave nature.
Wavelength = h / mv - ANSWER- Wavelength of Particles Formula
, Heisenberg's Uncertainty Principle - ANSWER- It is impossible to
simultaneously know the position and momentum of an electron.
Erwin Schrodinger - ANSWER- Attributed a wave function to electrons,
describing the probability of where an electron might exist.
Orbitals - ANSWER- Regions of high probability where electrons might
exist; broken into four levels: s, p, d, or f
Atomic Mass - ANSWER- The cumulative mass of all the particles in
the atom; found by adding the masses of the protons and neutrons.
Units: Atomic Mass Units (AMU)
Example:
helium = 2 protons + 2 neutrons
= 4 AMU
Atomic Number - ANSWER- The number of protons in the nucleus of
an atom, or the total nuclear charge. Also the number of electrons
surrounding the nucleus.
Isotopes - ANSWER- Atoms with the same number of protons but
different numbers of neutrons.
Example: carbon-12 (6 neutrons) vs carbon-14 (8 neutrons)
