Download Exercise 7

Chemistry for Physicists
Exercise 7
due date: Dec. 1st, 2016
1) For metals, the electrical conductivity decreases with increasing temperature, while for
semiconductors it's the opposite. How can this behavior be explained?
(1 point)
2) Why does the melting temperature of the transition metals within a period increase up to the
middle of the transition metals and then decrease. Explain according to the band theory.
(1 point)
3) Indicate the bonding geometry in the following compounds according to the VSEPR theory.
(2 points)
AsF5
SeF3+
CdBr2
IBr2SbCl64) Give the hybridization of the central atom of the following molecules. Which bonding
angles are expected?
(2 points)
BeF2
BeF3BeF42IF6+
5) Which of the following molecules will (in total) be polar? Draw the Lewis structure and
indicate the total dipole moment (or the polarity in each bond) of the molecule.
(1 point)
SCl2
SF6
ClF3
SO3
6) Determine the bond order of the following molecules:
O2
CNNO3NO
(1 point)
7) The exact calculation of the effective nuclear charge for the outermost electron for Si and Cl
yields 4.29 and 6.12. What do you expect if you consider
- the simple approach that every core electron contributes 1.00 to the screening constant and
valence electrons 0.00,
- Slater's rules?
What can you say about the accuracy of the two assumptions?
(1 point)