City College, Chemistry Department
Chemistry 10301, sections E*, Prof. T. Lazaridis
Third Midterm exam, Dec. 5, 2011
Last Name: _____________________________________________
First Name: _____________________________________________
SSN last 4: ______________________________________________
Note: There are 8 questions in this exam. Fill in your answer in the blank space
provided immediately following each question. 1/2 point will be subtracted every
time you report a numerical result with an incorrect number of significant figures.
Speed of light : 2.9979 X 108 m/s
Planck's constant : 6.626 X 10-34 Js
-24
1 amu = 1.66 x 10 g , Nav = 6.022 X 1023 mol-1 , En = -2.179 X 10-18 J/n2
Useful data:
1. (18) (a) (8) Are the following sets of quantum numbers permissible or
not? (write yes or no).
i) n=2
l=2
ml=2
ii) n=2
l=1
ml =0
iii) n=2 l=0 ml =1
iv) n=0
l=0
ml =0
(b) (6) How many orbitals are there in
i) the 3d subshell
ii) the n=4 shell
ii) the 4f subshell
(c) (4) Which of the following symbols represent possible orbitals and
which do not? In the latter case explain what is wrong.
i) 1p
ii) 8s
2. (12) (a) (3) Arrange the following atoms in order of increasing atomic
radius: K, B, Ga.
(b) (3) Based on their positions in the periodic table, circle the atom in the
following pairs that is expected to have the larger first ionization energy:
Na, Mg
F, Br
Si, Zn
(c) (3) Based on their positions in the periodic table, circle the atom in the
following pairs that is expected to have the greater metallic character:
Cd, Ge
O, Te
Ca, Mn
(d) (3) Based on their positions in the periodic table, arrange the elements
Cl, Al, In in order of increasing electron affinity.
3. (10) (a) (5) Most cell phones use electromagnetic radiation in the radiofrequency range, i.e. 100 kHz to 1 GHz. Calculate the maximum energy that
a photon in this range can have. Convert it to a per mol basis and compare to
the energy of a covalent bond (>100 kJ/mol). Based on this comparison, how
likely is cell phone radiation to cause breaking of chemical bonds in the
body?
4. (10) The minimum energy to dislodge electrons from potassium metal
(photoelectric effect) is 3.69X10-19 J. Will electrons be produced when
radiation of 600 nm wavelength shines on a clean potassium surface? Justify
your answer.
5. (10) What is the wavelength (in nm) of the radiation required for a
hydrogen electron to transition from the 1s orbital to a 2p orbital?
6. (25) Give the electron configuration and the orbital diagram (valence
electrons only) of the following elements or ions (use noble gas core
abbreviated notation):
a) (5) Cr
b) (5) Zn2+
c) (5) Tc
d) (5) S
2-
e) (5) Hg
7. (5) A beam of electrons and a beam of protons are moving with the same
speed. Which has the longer de Broglie wavelength?
8. (10) Use appropriate data to predict the enthalpy of the following reaction:
Na(g) + Cl(g)  Na+ (g) + Cl- (g)
Is the reaction endothermic or exothermic?