VSEPR - 1
Objective :
This lab is to study VSEPR and polarity of molecules with emphasis on sigma bonds and formal
charges.
Prelab Questions :
(PL1) Draw the Lewis dot structure of each compound (as having covalent bonds).
(a) BeH2 (b) BH3 (c) GeH2 (d) CH4 (e) NH3 (f) H2O (g) PCl5
(h) SF4 (I) ClF3 (j) XeF2 (k) SF6 (l) BrF5 (m) XeF4
(PL2) If you are using the ball-and-stick model, what does each ‘ball’ represent? Each “stick”? Be
very specific.
(PL3) What does the word “VSEPR” stand for?
(PL4) When and why do we want to discuss VSEPR of a compound?
(PL5) Are all single bonds considered sigma bonds? Explain.
(PL6) For the lab, you were told to draw all compounds as having covalent bonds. Draw the Lewis Dot
structure of BeH2 as ionic compound.
Post Lab Questions :
(Q1) Explain why lone pairs might take up more space than the bonding pair.
(Q2) What is not clear about a question that states ‘discuss the VSEPR of acetic acid, CH3COOH’ ?
(Q3) Draw the Lewis Dot structure of O3 with a linear ( I don’t mean the shape is linear) backbone
( O-O-O backbone) and with a cyclic backbone (three oxygen atoms in a ring). Discuss VSEPR of
both structures. Discuss the bond angles. Can you tell which structure is more stable?
(Q4) What type of orbitals overlap to form a sigma bond?
Summary :
A separate summary sheet will be given after the lab. Fill it out without looking at your lab
notebook. Make a photo copy of the sheet. Tape the original to the notebook and turn in the copy
as report.
Abstract:
No more than 100 words stating why the lab was done, what was done, the major result(s), and
conclusion(s).
Reflection Statement:
One thing I might do differently next time is …… because…….