1. (10 points) Platinum, which is widely used as a catalyst, has a work function φ (the minimum
energy needed to eject an electron from the metal surface) of 9.05 × 10-19 J. What is the
longest wavelength of light which will cause electrons to be emitted?
2. The power output of a laser is measured by its wattage. The number of Joules of energy it
radiates per second (1 Watt = 1 J s-1). A 10-Watt laser produces a beam of green light with a
wavelength of 520 nm.
a) (5 points) Calculate the energy carried by each photon
b) (6 points) Calculate the number of photons emitted by the laser in one second.
3. (5 points) What is the minimum energy (in J) needed to ionize a hydrogen atom from the n =
2 state according to the Bohr theory of the hydrogen atom?
4. (10 points) Please provide the correct answer to the following questions.
(a) Atomic orbitals developed using quantum mechanics to
A. Describe regions of space in which one is most likely to find an electron.
B. Describe exact paths for electron motion.
C. Give a description of the atomic structure which is essentially the same as the Bohr
model.
D. Allow scientists to calculate an exact volume for the hydrogen atom.
E. Be in conflict with the Uncertainty Principle.
Correct Answer:__________________
(b) The energy of an electron in the hydrogen atom is determined by
A.
B.
C.
D.
E.
The principal quantum number (n) only.
The angular momentum quantum number (l ) only.
The principal and angular momentum quantum numbers (n & l ).
The principal and magnetic quantum numbers (n & ml).
The principal, angular momentum and magnetic quantum numbers.
Correct Answer:__________________
(c) In the quantum mechanical treatment of the hydrogen atom, the probability of finding an
electron at any point is proportional to the wavefunction, Ψ.
Correct
True False
Answer:__________________
(d) In the quantum mechanical treatment of the hydrogen atom, the energy depends on the
principal quantum number n but not on the values of l or ml.
Correct
True False
Answer:__________________
(e) An atom of element with atomic number 33 (As) is in its ground electronic state. Which
one of the following sets of quantum numbers could not apply to any of its electrons?
a.
n=2
l=1
ml = -1
ms = +½
A.
B.
C.
D.
E.
b.
n=3
l=0
ml = 0
ms = -½
c.
n=3
l=2
ml = -2
ms = -½
d.
n=4
l=0
ml = 0
ms = -½
e.
n=4
l=2
ml = 1
ms=+½
a
b
c
d
e
Correct Answer:__________________
5. (10 points) Please provide correct answers for the following questions
(a) What is the correct order of decreasing size of the following ions?
A.
B.
C.
D.
E.
P3- > Cl- > K+ > Ca2+
Ca2+ > K+ > Cl- > P3K+ > Cl- > Ca2+ > P3K+ > Cl- > P3- > Ca2+
None of these is correct.
Correct Answer:__________________
(b) Based on electronegativity trends in the periodic table, predict which of the following
compounds will have the greatest % ionic character in its bonds.
A.
B.
C.
D.
E.
H2O
LiI
CaO
RbF
HCl
Correct Answer:__________________
(c) Select the most polar bond amongst the following.
A.
B.
C.
D.
E.
C-O
Si-F
Cl-F
C-F
C-I
Correct Answer:__________________
(d) Elements with the highest first ionization energies are found in the ___________ region of
the periodic table.
A.
B.
C.
D.
E.
Lower left
Upper left
Center
Lower right
Upper right
Correct Answer:__________________
(e) Which of the following elements is the most electronegative?
A.
B.
C.
D.
E.
S
Ru
Si
Te
Cs
Correct Answer:__________________
6. (10 points) Write the ground state electron configuration for the following ions:
Li+
B+
F−
Al3+
S−
7. (5 points) Write the electron configuration of the first excited state of
Be2+
He+
F−
O2Ar+
8. (15 points) Complete the following tables:
n
2
l
1
Label
No. of orbitals
3d
4
n
1
2
7
l
0
Radial Nodes
Angular Nodes
1
3
1
1
3
9. (10 points )In a universe in which Planck’s constant has the value of h = 1.0 J s, what
would be the de Broglie wavelength of a baseball of mass 170 g moving at a speed of 30 m s-1?
10. PCl2F3 does not have a dipole moment.
a) (3 points) Use VSEPR to predict and carefully draw the structure consistent with this
data.
b) (2 points) Why does your structure have no dipole moment? Explain your answer
11. (10 points) Write the Lewis dot structure of sulfuryl chloride, SO2Cl2 , all of its resonance
structures and assign formal charges