Download Reading: sections 6.5-6.6 A. An orbital is composed

24/09/2010
Reading: sections 6.5-6.6
As you read this material, ask yourself the following
questions:
 What are wave functions and orbitals, how do orbitals differ from
orbits?
 What can we learn about an electron from a wave function?
 What properties of the electron do the principal quantum number,
the angular momentum quantum number and the magnetic quantum
number determine. What values can each of these quantum numbers
have, how are their values related?
 What are the shapes of the orbitals for different values of the
angular momentum quantum number (different subshells)? Sketch
these shapes. What labels do we give these subshells?
 How do the energy levels differ in many electron atoms?
 What is the fourth quantum number and what values can it have?
 When assigning energies to electrons, what are the implications of
the Pauli Exclusion principle?
Chem 101
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What is the difference between an orbit (Bohr model) and an
orbital (quantum mechanical model)?
A.
B.
C.
D.
E.
An orbital is composed of some integral number of orbits.
An orbit is a well-defined circular path around the nucleus
while an orbital is a wave function that gives the probability of
finding the electron at any point in space.
An orbit is a well-defined circular path around the nucleus
while an orbital is the object (electron) that is moving around
the nucleus.
There is no difference between the definitions of the terms
“orbit” and “orbital.” They simply were proposed by different
scientists.
“AL”.
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What is the difference between an orbit (Bohr model) and an
orbital (quantum mechanical model)?
B. An orbit is a well-defined circular path around the nucleus while
an orbital is a wave function that gives the probability of finding the
electron at any point in space.
How many maxima would you expect to find in the radial
probability function for the 4s orbital of the hydrogen atom?
How many nodes would you expect in the 4s radial
probability function?
A.
B.
C.
D.
E.
three maxima and three nodes
three maxima and four nodes
four maxima and three nodes
four maxima and four nodes
OK; so the 1s orbital has one maximum (at the nucleus) and
no nodes (we don’t count the one at infinity). So the 2s
orbital must be different. Is it the same shape?… let’s check
my notes… yes, spherical. Does it have a node? One? That
would make it different, I suppose. Where is it? Somewhere
between the nucleus and infinity, I guess, but where? The
suspense is killing me… maybe it doesn’t matter. All right
then, let’s put it at an arbitrary distance “x” from the nucleus.
If there is a node there must be at least two maxima. So far
so good. Moving on to the 3s orbital… again, same shape,
but somehow different, I’m guessing another node… so if it
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How many maxima would you expect to find in the radial
probability function for the 4s orbital of the hydrogen atom?
How many nodes would you expect in the 4s radial
probability function?
C.
four maxima and three nodes
node = probability of
finding an electron is 0
For an s orbital the
number of nodes is
given by n – 1
What is not possible? (Once you’ve solved that pass the
time by sketching and naming the others)
A.
B.
C.
D.
E.
n=2, l=1,m=-1
n=3, l=2,m=0
n=3, l=1,m=2
n=4, l=0,m=0
n=1, l=0,m=0
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What is not possible? (Once you’ve solved that pass the
time by sketching and naming the others)
A.
B.
C.
D.
E.
n=2, l=1,m=-1 2px(or y or z)
n=3, l=2,m=0 3dxy (or xz or yz or z2 or x2-y2)
n=3, l=1,m=2
n=4, l=0,m=0
4s
n=1, l=0,m=0
1s
What is not possible? (n, l, ml) (Once you’ve solved that
pass the time by sketching and naming the others)
A.
B.
C.
D.
E.
3,2,1
1,0,0
2,1,2
4,3,-3
5,0,0
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What is not possible? (n, l, ml) (Once you’ve solved that
pass the time by sketching and naming the others)
A.
B.
C.
D.
E.
3,2,1
1,0,0
2,1,2
4,3,-3
5,0,0
3d (any of xy, yz, xz, z2, or x2-y2)
1s
Not possible
4f (let’s not discuss the ml values)
5s
What is the allowed set of quantum numbers? (n, l, ml) (Once
you’ve solved that pass the time by sketching it)
A.
B.
C.
D.
E.
1,1,0
2,3,1
3,1,2
3,1,1
2,1,-2
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What is the allowed set of quantum numbers? (n, l, ml) (Once
you’ve solved that pass the time by sketching it)
A.
B.
C.
D.
E.
1,1,0
2,3,1
3,1,2
3,1,1
2,1,-2
3p (can be x,y or z)
y is drawn
What does the change in colour of the orbital represent in
the picture below?
A.
B.
C.
D.
E.
The variations in pink color do not
represent any significant physical feature.
The lighter pink regions represent more
positively charged areas of the p-orbital.
The probability of finding an electron in the
interior of a p-orbital lobe is less than it is
on the edges.
The probability of finding an electron in the
interior of a p-orbital lobe is greater than it
is on the edges.
Artistic license.
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What does the change in colour of the orbital represent in
the picture below?
B. The probability of finding an electron in the
interior of a p-orbital lobe is greater than it is on
the edges.
Based on the structure of the periodic table, which orbital
becomes occupied first?
A.
B.
C.
the 5d orbital
the 6s orbital
the 5f orbital
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Based on the structure of the periodic table, which orbital
becomes occupied first?
B.
the 6s orbital
For a many-electron atom, can we predict unambiguously
whether the 4s orbital is lower or higher in energy than the
3d orbitals?
A.
B.
C.
Yes
No
Maybe
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