1. QUESTION:
Which of the structures below is valid for the HOCl molecule? A. 1, B. 2, C. 3, D. 4
14 v.e.
12 v.e.
10 v.e.
SCRIPT: 3-5-2
Which of the structures shown here is valid for the H O Cl molecule?
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Hydrogen can only form one single bond. So, right away, we can eliminate structures 4, where it is shown to have a double bond.
CLICK CLICK
We can also eliminate structure 5, where it is shown to have two single bonds.
In both cases, the hydrogen atom appears to be surrounded by four
electrons, when it should only be surrounded by only two. Hydrogen follows the duet rule.
Now, if we examine the atoms in the remaining choices ---- they all follow the octet or duet rule. So, how do we determine which one is right?
Let’s count the number of valence electrons…
We refer to a periodic table, we determine the number of valence electrons.
Hydrogen has one,…
Oxygen, which belongs to group six A, has six...
And chlorine, which belongs to group seven A, has seven.
One plus six plus seven equals fourteen.
HIGHLIGHT 14
Therefore, the HOCl molecule has a total of fourteen valence electrons.
Structure 1 has fourteen valence electrons, ….
Structure 2 has twelve valence electrons….
And Structure 3 has ten valence electrons…
Of the remaining choices, only structure 1 has fourteen valence electrons --- the correct answer is structure 1.
PAUSE 2 seconds
END RECORDING
H can only form single bond: 4 and 5 are wrong.
Number of valence electrons: H-1, O-6, Cl-7; Total=14 Structures 2 and 3 have less than 14 valence electrons shown.

2. Video ID: © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08