1. Sketch the Lewis structure of the molecule BrF3, showing in
detail: (a) the electron pairs on Br
(b) molecular geometry
(c) formal charge on Br
(d) the polarity of the molecule (polar or non-polar)
2. Use the average bond energies to calculate the enthalpy
change (AH) for the following
H H H H
H - c = C + H2O(g) ------- H-C-C-H
H H H (g)
Relevant bond energies:
H-H 432 KJ/mol
C-C 436 KJ/mol
C=C 602 KJ/mol
C-H 411 KJ/mol
3. Which of the following pairs are isoelectronic?
(a) Ne and Ar
(b) Na+ and K+
(c) K+ and Cl
d) Li+ and Ne
(e) Be2+ and Na+
4. A bond with an electron pair that is equally shared by two
(c) coordinate covalent
5. The molecular geometry in the ammonium ion NH4+ is:
(a) square pyramidal
(b) trigonal planar
(c) trigonal pyramidal
(e) square planar
6. In which of the following compounds is the octet rule
7. Draw two resonance structures to describe the bonding in sulfur dioxide SO2.
8. Write the ground state electron configuration of the following:
9. All of the following species are isoelectronic, except:
10. In the Lewis formula for the perchlorate ion ClO4-, what is
the total number of
valence electrons (including all atoms)?
11. In the Lewis formula for ClF3 how many lone pairs are around the central atom?
12. What is the formal charge on the Bromine atom in the perbromate ion BrO4-?
13.What is the hybridization of carbon in CH4? Draw an orbital diagram to show the hybrid orbitals overlapping with the hydrogen 1s orbitals. Why do we need t ouse hybrid orbitals to explain the tetrahedral molecular geometry?
14. Complete the molecular orbital diagram to explain the
bonding in the N2 molecule
(triple bond). Clearly show all electrons from the valence shell of each nitrogen atom.