[Grammar] It is ... who/that ...

[inase]

I am wondering if all the following sentences sound ok.
Logically, since these are emphatic expressions, whether they are good or bad may be judged by eliminating "it is" and "who/that." Therefore, I assume that only the odd numbers are correct.

1. It is I who am to blame.
2. It is I who is to blame.
3. It is I that am to blame.
4. It is I that is to blame.
5. It is you who are to blame.
6. It is you who is to blame.
7. It is you that are to blame.
8. It is you that is to blame.

Inase

 

[GoesStation]

I'd say "it's my/your fault."

 

[teechar]

Or,
I am to blame for ...

 

[jutfrank]

Whether they sound okay and their logical correctness are not necessarily compatible.

If you're asking whether they sound okay, I can give you my personal judgement:

None of them sound great but the even numbers sound better than the odd. That is, they sound a bit less formal. Also naturally possible in casual conversation is It's me who's to blame.

 

[inase]

Whether they sound okay and their logical correctness are not necessarily compatible.

If you're asking whether they sound okay, I can give you my personal judgement:

None of them sound great but the even numbers sound better than the odd. That is, they sound a bit less formal. Also naturally possible in casual conversation is It's me who's to blame.

In that case, do you say "it is me who am to blame," or "it is I who am to blame?"
I am curious about to what extent the verb in the sub clause follows the person of the subject in the main clause.

 

[jutfrank]

I would say It's me who's to blame or possibly It is I who am to blame, but not It's me who am to blame. I don't think anyone would use the latter.