[John623]

I'm trying to work out how strict the rules are, and if I can do everything I am showing in these diagrams. Many of them are the same thing shown differently. I am particularly concerned about 3) and 5)

[mjc123]

2 is correct, 1 is wrong. A Cl atom abstracts a H atom from methane. It does not abstract an electron to give methyl radical and free H⁺ and Cl^-
4 is to the best of my knowledge the correct mechanism, 3 and 5 are wrong. The reaction does not involve free protons or hydride ions.
7 and 8 are not reactions, they are resonance hybrids. They are formally interchangeable by pushing pi bonds around, as in 7 (by the way, you have a positive charge too many on the RHS). They do not involve di- or polyradicals (or only as very minor, because very high-energy, contributors). 6 is totally implausible.
These are not "the same thing shown differently", they are different mechanisms, some of which are right and some wrong.

[John623]

What I did for 1 was, I looked at 2 and I tried to break the reaction down into more steps. Is there not a way to do that? I find them easier to follow when I try to break them down into more steps.

Would you say that this was the correct way to show 1) as a breakdown of 2) instead?



I got 3 and 4 from here http://www.chem.wisc.edu/areas/reich/handouts/elecpush/epush-1.htm
The website says that 4 is a shorthand version of 3.

and then I invented 5 myself using what I thought was a diagram that obeyed all the rules of curly arrow diagrams. I thought that perhaps, if you know the rules of curly arrow diagrams (and follow them), then as long as you get the correct final molecule, then perhaps it's correct.

I found 7 on the internet, and I tried to break it up into more steps, creating 6.
I thought that when you have a curly arrow from one bond to another bond, you are basically showing a short hand version of a longer reaction. I thought I was showing this with 6.

I'm not sure if I'm violating the rules of the curly arrow diagrams, or if I'm following the rules properly, but violating some other rule. What kind of material should I be looking at to fix whatever I'm doing wrong?

[mjc123]

Why do you want to "break a reaction down into more steps"? If it is a single-step reaction, this is to misunderstand it, not to understand it better. There is no correct way to show a "breakdown" of reaction 2. The abstraction of a H atom from methane by a Cl atom is a concerted single-step process; to represent it as occurring in two steps is simply wrong. Free H atoms or protons are not involved.
Likewise I believe (willing to be corrected if wrong) that the hydride transfer in 4 is a single step reaction. H^- is a very reactive species and I don't think it would spontaneously dissociate from R₃BH^-. Your reference says 4 is shorthand for consecutive or simultaneous bond breaking and making, without saying whether it thinks that particular case is consecutive or simultaneous.
But 1 and 5 are definitely wrong. Radicals or electrophiles do not simply take electrons from bonds (singly or in pairs) leaving the previously bonded atoms separate. (I won't swear this never happens but I can't think of an example in common organic reactions.) Rather the H atom is transferred, with 1 or 2 electrons, to the attacking species.
And do not, without very good reason (e.g. absorption of light in a photochemical reaction) show bonds spontaneously dissociating into two radicals. This is a highly energetic and improbable process.