Chemistry with Lab WGU c832 exam with
complete solutions
principal quantum number (n) - ANSWER- symbolized by n, indicates the main
energy level occupied by the electron. positive integers (1,2,3...)
shell - ANSWER- set of orbitals with the same principal quantum number, n.
atomic orbital - ANSWER- a region of space in which there is a high probability of
finding an electron. mathematical function that describes the behavior of an
electron in an atom, wave function.
angular momentum quantum number (l) - ANSWER- the quantum number that
indicates the shape of an orbital. (0,1,2...n-1)
subshell - ANSWER- mathematical description of an atomic orbital that describes
the shape of the orbital; it can be used to calculate the probability of finding the
electron at any given location in the orbital, as well as dynamical variables such
as the energy and the angular momentum.
s orbitals are what shape? - ANSWER- spherical region of space with high
electron density, describes orbitals with l=0. An electron in this orbital is called
an s electron.
p orbital shape - ANSWER- peanut or dumbbell shaped region of space with high
electron density, describes orbitals with l =1.
d orbital shape - ANSWER- 4 leaf clover. l=2
magnetic quantum number (ml) - ANSWER- the quantum number that indicates
the orientation of an orbital around the nucleus; orbitals having different values
of ml but the same subshell value of l have the same energy (are degenerate), but
,this degeneracy can be removed by application of an external magnetic field. (l, l-
1,...,-l)
spin quantum number - ANSWER- has only two possible values (+1/2, -1/2) which
indicate the two fundamental spin states of an electron in an orbital. ms.
Pauli Exclusion Principle - ANSWER- no two electrons in the same atom can have
the same set of four quantum numbers.
degenerate orbitals - ANSWER- orbitals that have the same energy
electron density - ANSWER- a measure of the probability of locating an electron
in a particular region of space, it is equal to the squared absolute value of the
wave function.
f orbital - ANSWER- multilobed region of space with high electron density,
describes orbitals with l = 3. An electron in this orbital is called an f electron
Heisenberg uncertainty principle - ANSWER- states that it is not possible to know
precisely both the velocity/momentum and the position of a particle at the same
time
quantum mechanics - ANSWER- field of study that includes quantization of
energy, wave-particle duality, and the Heisenberg uncertainty principle to
describe matter.
orbital - ANSWER- an allowed energy state of an electron in an atom or molecule.
not the same as orbit.
Why did the Bohr model of the atom ultimately fail? - ANSWER- it required
knowing the position and momentum of an electron.
What does the quantum mechanical model show us? - ANSWER- The probability
of finding the electron in a region of space.
What information does Schrodinger's equation combine? - ANSWER- Kinetic
energy, potential energy, and wave properties.
wave function - ANSWER- describes how the electrons move within an atom.
probability maxima - ANSWER- the large "hills" on the graph.
,radial nodes - ANSWER- spherical region where the electron is not likely to be
found.
nodal plane - ANSWER- a planar surface on which the probability of finding an
electron is zero.
atomic orbital shapes - ANSWER- S-Orbital: all spherical. probability of finding an
electron depends on distance from the nucleus not direction, ml = 0, only 1s
orbital per shell
P-Orbital: dumbbell shaped, three orbitals: 2px, 2py, 2pz
D-Orbital: five orbitals, more complex than s and p orbitals
F-Orbitals: seven D-Orbitals, complex shapes.
what is an orbital? - ANSWER- the probability of finding an electron in a region.
What are the names for the 3 quantum numbers in the Schrodinger's equation? -
ANSWER- principal, angular, magnetic
What are the permissible values for the angular quantum number (l) when n=4? -
ANSWER- 0, 1, 2, 3
How many angular modes do the d orbitals have? - ANSWER- 2
What are the values for (ml) for a d orbital? - ANSWER- -2, -1, 0, 1, 2
There are 3 p orbitals that are aligned with their major axes along the x, y, and z
axes. What is the origin of these 3 p orbitals? - ANSWER- They are the solutions
for the 3 values of the magnetic quantum number.
What are the permissible values for the angular quantum number (l) when n=3? -
ANSWER- 0, 1, 2
What are the values for (ml) for a p orbital? - ANSWER- -1, 0, 1
What are the permissible values for the quantum number (l) when n= 2? -
ANSWER- 0, 1
, What is the difference between the 2p and a 3p orbital? - ANSWER- The 3p orbital
is farther from the nucleus than the 2p orbital.
quantized - ANSWER- allowed to exist only at certain discrete (non-continuous)
values.
electron spin - ANSWER- A property of the electron that makes it behave as
though it were a tiny magnet. The electron behaves as if it were spinning on its
axis; electron spin is quantized.
electron spin quantum number (ms) - ANSWER- the fourth quantum number of an
electron having a value of +1/2 or -1/2 corresponding to up and down electron
spin.
Why is it important to understand where the electrons are? - ANSWER- Atoms
bond through the interaction of electrons. Knowing where the electrons are in an
atom allows prediction of how atoms will bond by understanding which electrons
are available.
What are the legitimate values for the spin quantum number (ms)? - ANSWER-
+1/2 and -1/2
Which set of quantum numbers is possible for the 2 electrons of helium? -
ANSWER- (1, 0, 0, +1/2) and (1, 0, 0, -1/2) Both electrons are in the 1s orbital (as
indicated by the first 3 numbers), but one has spin up (+1/2) and the other has
spin down (-1/2)
Which of the following statements best states the Pauli Exclusion principle? -
ANSWER- Each electron in an atom must have a unique set of quantum numbers
describing it.
What is the difference between a 2s orbital and a 2p orbital? - ANSWER- They
have different angular momentum quantum numbers. All S orbitals have an
angular momentum quantum number of 0, whereas all P orbitals have an angular
momentum quantum number of 1.
Hund's Rule - ANSWER- states that single electrons with the same spin must
occupy each equal-energy orbital before additional electrons with opposite spins
can occupy the same orbitals.
