(a) What are “valence electrons”?

Question

Accepted Answer

Welcome back everyone in this example. We need to identify the statement that best describes valence electrons. Beginning with statement it reads that valence electrons are inner shell electrons and don't participate in chemical bonding. We would automatically correct this to say that valence electrons are actually outer shell electrons and they actually do participate in bonding. What statement is describing is actually core electrons. So we're going to rule out statement A. Because this does not best describe valence electrons. It best describes core electrons moving onto statement B. It's reads that valence electrons are paired electrons so we want to also recognize that this is also a false statement and that is because this should be corrected to say that core electrons are paired electrons because core electrons are placed in fully filled sub shells whereas valence electrons are placed in the outer sub shells and can be paired. So valence electrons can either be paired or they can be uncared because they are outer shell. So statement be also does not accurately describe valence electrons. Let's move on to statement C. It reads that valence electrons are paired electrons and we would definitely agree with that. We just stated that they can either be paired or impaired. So statement C is looking like a good prospect for a true answer choice. Moving on to statement D. It says that vance electrons are outer shell electrons so we can so far agree with that that participate in chemical bonding. So we actually would also fully agree with statement D. Now going back to statement See we're going to say that this is half true actually because we want to recognize that they can also be uncared or sorry, they can also be paired as we stated above, and Choice B. So that means that statement C isn't going to be the best statement to describe valence electrons because it's only half true, and so will rule out Choice C, meaning that D is going to be the only correct choice, which, as a statement best describes valence electrons being outer shell electrons that can participate in chemical bonding, whereas our core electrons do not ever participate in chemical bonding. So if you have any questions, please leave them down below and I'll see everyone in the next practice video.

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