eli5: how does the number of unpaired valance electrons determine the number of bonds an atom makes?
In: Chemistry
I believe your question is : why does a molecule want such a specific electron configuration that is will want to create valence shells in the first place? If that is your question, then the eli5 answer would be these electronic configurations represent a low energy point that the nucleus/electron cloud system wants to reach. A bit like why are bubbles round and not square. It’s a system trying to minimize its energy.
Think of it as every element wants to be a like a “noble gas”(those elements in the far right hand column of a chemistry table.) and have a full outer electron shell. The unpaired electrons correspond to how far away from that column that particular element is. So for example, carbon is 4 steps away from its nearest noble gas, or full shell, it has 4 unpaired elections. In order to get there it needs to borrow electrons from somewhere.
The somewhere is the element(s) that it bonds with to get up to that “gas”/full shell. In this case neon. The borrow is more like a share cause the other element also wants to get to a full shell and is not going to completely give up electrons.
Note: I am not a chemistry major, and I am drawing on as best I remember from HS & gen Ed chemistry class in college.
By the number they need in order to maintain a stable eight electron shell. C – C is a triple bond because each bond counts for 2 electrons so they have 2 free electrons plus a 3 bonds (which counts for 2) = 8.
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