Edition By Rayner-Canham, Geoff 9781464125577 ALL
Chapters .
Who is accredited with the organization of the modern periodic table? - ANSWER: Dmitri Mendeleev
Describe a Metal - ANSWER: Lustrous, malleable, ductile, good conductors of heat and electricity.
Except for mercury, all metals are solids are room temperature.
Describe a Nonmetal - ANSWER: Located in the upper right-hand corner of the periodic table. Most
nonmetals are poor conductors of heat and electricity. Can be in gas, liquid, or solid state at room
temperature.
Describe Metalloids - ANSWER: Dull-appearing brittle solids at room temperature. Conduct electricity
better than non-metals but not as well as metals.
What did Dmitri Mendeleev contribute to chemistry? - ANSWER: Proposed modern organization of
the periodic table based on chemical properties; only knew molecular weights and reactivity;
proposed some missing elements
What did Lothar Meyer contribute to chemistry? - ANSWER: Proposed organization of the periodic
table based on physical properties
What did J.J. Thomson contribute to chemistry (1904)? - ANSWER: Cathode ray tube experiment with
electrons; particles were emitted regardless of electrode material; mass was 1/1000 that of a
hydrogen atom; particles were determined to be negatively charged; Plum Pudding Model - negative
particles randomly within positive atom
What did Ernest Rutherford contribute to chemistry (1911)? - ANSWER: Gold foil experiment; shot
particles at gold foil - most went through the foil but some bounced back, indicating that the mass of
an atom was concentrated in the nucleus and carried a charge; electrons orbit around a positive
center
What did Rydberg contribute to chemistry (1888)? - ANSWER: Rydberg equation for light quantization
of atoms; each element emits its own light when excited; find specific wavelengths of light by burning
salts; spectroscopic observations on hydrogen atoms suggest that an electron can occupy only certain
energy levels and that the emissions of discrete frequencies of electromagnetic radiation occurs when
an electron makes a transition between these levels
What did Bohr contribute to chemistry (1913)? - ANSWER: Electrons bound to atoms can have only
certain specific energy values ("quantized"); Bohr explained the Rydberg equation and quantization;
model shows that electrons have very specific orbits
What did Einstein contribute to chemistry (1905)? - ANSWER: Photoelectric effect - light energy, not
light intensity, is needed to excite electrons; light is particle-like in its behavior; electrons resonate
around nucleus
What did de Broglie contribute to chemistry (1924)? - ANSWER: Wave-particle duality - light waves
have particle as well as wave properties; electrons have as well as particle properties; equation
relates wavelength to mass; electrons resonate around nucleus
What did Heisenberg contribute to chemistry (1927)? - ANSWER: Heisenberg uncertainty principle -
the position of an electron cannot be precisely defined; the more accurately we know position of a
, particle, the more uncertain we are about its motion and vice versa; uncertainty is a feature of all
objects but becomes noticeable only for very small objects
What did Schrodinger contribute to chemistry (1925)? - ANSWER: A wavefunction (psi) contains all
the dynamical information possible about the electron including where it is and what it is doing; the
energy (E) defines the electron binding energy to the nucleus; psi is a solution to the equation;
Schrodinger equation can be solved exactly for H-like systems (1 electron); psi is the "atomic orbital";
physically acceptable solutions exist only for certain values of E ("quantized")
Each wavefunction (psi) or atomic orbital can be specified by what three quantum numbers? -
ANSWER: n: principle quantum number (positive integer)
l: angular momentum quantum number (integer from 0 to n-1)
m: magnetic moment quantum number (integer from -l to +l)
All orbitals with a given n belong to the same shell; the orbitals belonging to each shell are classified
into sub-shells distinguished by a quantum number l; individual orbitals are distinguished by the value
of m
The ___________________ expresses the variation of the orbital with distance from the nucleus. -
ANSWER: Radial Wavefunction; depends on r and given by n and l
The ________________ expresses the orbital's angular shape. - ANSWER: Angular Wavefunction;
depends on theta and phi and given by l and m
Principle Quantum Number (n) - ANSWER: Must be a positive integer; indexes energy and size of
orbital; lower n = closer to nucleus (on average) and lower in energy
Orbital Angular Momentum or "Azimuthal" Quantum Number (l) - ANSWER: Can be zero or any
positive integer small than n; indexes shape of orbital; s sub-shell l=0; p sub-shell l=1; d sub-shell l-2; f
sub-shell l=3
Magnetic Quantum Number (m) - ANSWER: Can have any positive or negative integral value between
0 and l; indexes orientation of orbital; the number of allowed values for m for that particular value of l
determines the number of degernerate (having equivalent energy) orbitals
Spin and Spin Magnetic Quantum Number - ANSWER: s = 1/2; m = +1/2 or -1/2 (half integers); indexes
spin direction of electron within an orbital; spin up or spin down
One Electron Orbital Approximation - ANSWER: Assume each electron occupies a hydrogen-like
orbital; the lowest energy electron configuration is call the "ground state"; allowed energies are
specified by the principle quantum number, n
Shielding (Screening) - ANSWER: Separates S orbitals from P orbitals; the inner 1s electrons "shield"
other electrons from the nucleus (+) charge; electrons that are not shielded are lower in energy; the
presence of an electron inside the orbitals of other electrons is called penetration (how well electrons
can see the nucleus); as a result of shielding and penetration, the order of energies in many-electron
atoms is typically ns < np < nd < nf
Effective Nuclear Charge (Z effective) - ANSWER: Higher nuclear charge lowers orbital energy
(stabilizes the system) by increasing nucleus-electron attractions; Z(eff) = Z - sigma; sigma = shielding
constant; additional electron in the same orbital raises the orbital energy through electron-electron
repulsions; additional electron in inner orbitals shield electrons more effectively than do electrons in
the same sublevel
Shielding Trends - ANSWER: Decreases as n increases because, as n increases, electron density
decreases (larger orbitals); decreases as l increases because the lower l has some electron density
closest to the nucleus and is more spherical in shape