Chemistry 20 – Molecules & Compounds
HMWK
3-5
– Molecular Shapes
Objectives:
> draw Lewis structures for molecules
> use the VSEPR Theory to predict shapes of molecules
1. What does VSEPR stand for? According to the VSEPR Theory, why do shapes form?
2. Using your knowledge of VSEPR theory,
i) draw the Lewis structure for each, and
ii) predict the shape of the following:
a) Hydrogen sulfide, H2S
b) Silicon tetrahydride, SiH4 (if Si is hybridized like ‘carbon’)
c) Nitrogen gas, N2
d) Boron triiodide, BI3
e) Carbon dioxide, CO2
f)
Hypochlorous acid, HOCl
g) Methyl chloride, CH3Cl (with “carbon” as the central atom)
h) Boron trihydride, BH3
i)
Sulfur dioxide, SO2
j)
Indium chloride, InCl3 (if indium is hybridized like ‘boron’)
k) Beryllium chloride, BeCl2
l)
Dinitrogen dihydride, N2H2 (with “nitrogen” as the 2 central atoms)
m) Phosphorous pentachloride, PI5
n) Ethanol, CH3CH2OH (with “any carbon” as the central atom, and all carbons connected)
o) Sulfur hexaflouride, SF6
3. (Challenge) Using the diagram/picture on the back page, find the shapes of these ‘irregular’
molecules, using the same techniques in class.
a) Sulfur pentachloride, SCl5 (use the chart below to help identify the shape)
b) XeF4
c) ClF3