Bioorg Chem
Dr. Milkevitch
Sept 11, 2009
Problem Set 1
Name_______________
Due: Sept 18, 2009
Note: Working in groups is encouraged. If you choose to work in groups, indicate
who the group members were on the top of the page.
1) Complete the following table: (8 pts)
Protons
19
21
Neutrons
20
58
45
Electrons
Element
45
34
21
2) Answer the following: (2 pts each)
a) What does the principle quantum number “n” stand for??
b) What does the azimuthal quantum number “l” stand for?
c) What does the magnetic quantum number “ml” stand for?
3) Given that the principle quantum number n = 6:
(2 pts) a) List all possible values of l.
(2 pts) b) Interpret the values of l in terms of orbital shape (NOTE: you will have an l
value for which you do not know the orbital shape).
(9 pts) c) List all possible values of ml.
4) Is the following a true statement? Explain your decision (3 pts).
for n=4, the values of ml are -3, -2, -1, 0, 1, 2, 3
5) Draw electron configurations for the following elements. Use the correct shorthand
notation. (3 pts each)
a) Germanium
b) Rubidium
c) Chromium
d) Tin
e) Bromine
6) Draw Lewis Structures for the following compounds. Include all lone pairs of
electrons. Calculate formal charges on all atoms in the molecule. (4 pts each)
a) CH3-
b) N2
c) HCN
d) C3H4 (hint: there is one triple bond in this structure)
e) H2CO3 (this is an oxyacid, carbonic acid)
f) CH3CNO
g) ClO3-
7) Draw the Lewis structures of the following compounds. Using VESPR Theory, predict
the 3-dimensional structure of the compound. Indicate the bond angles. (2 pts each)
a) SiH4
b) BeCl2
c) BBr3
d) H2SO4 (another oxyacid)
8) Using the Pauling Electronegativity Scale, predict the dipole moment in the following
bonds. Use the correct notation to indicate the direction of the dipole moment (2 pts
each).
a) C – C
b) O – Cl
c) C – B
d) C – Ca
9) Carbon tetrachloride (CCl4, a solvent used in the past for dry cleaning) does not have a
molecular dipole moment. Does the related compound, CHCl3 have a molecular dipole
moment? Explain using Lewis structures, bond dipole moments, and what you know
about how molecular shape can affect polarity. (3 pts)
10) For the following molecules, 1) describe the molecular shape and 2) predict whether
the molecule has a molecular dipole moment. Drawing the Lewis structure will probably
help you determine if a dipole moment is present (2 pts each).
a) CH2Br2
b) OF2
c) SiHF3
d) C2H2