Trust

1. We should trust scientists because scientists says so

2. But that will be appel to authority.

3. Therefore we shouldnt trust any scientists

This argument is invalid because the conclusion is not implied by the premises. Taking a claim as true simply because authority said so is a fallacious appeal to authority, but the inference that because the reasoning is fallacious, the claim is wrong, is also fallacious - the argument from fallacy. It does not follow that X is incorrect because it was derived illogically. The fact the conclusion states we should not trust any scientists makes it even more fallacious.

The argument is also unsound because the premises themselves are questionable. We shouldn't "trust science because scientists say so" - we should trust the scientific method because we believe it is accurate and reliable. Scientists, being experts in their fields, are trusted to carry out research using this accurate and reliable process. So while it may be reasonable, for example, to trust the word of Richard Dawkins on evolution, evolution itself so not true because he said it - it is true simply because it is, and we trust him to effectively communicate facts about evolution to us.

At best, there are missing links; however, I think that it's really a big time non sequitur that includes questionably true premises.  The absence of quantifiers leave the whole sequence open to an ambiguity fallacy because of uncertainty over which scientists? some of them?, all of them?

Statement 1 is really a blend of a premise and an argument: Scientists say we should trust scientists.  Therefore, we should trust scientists.  Then, there's the further ambiguity of "Trust scientists to do what?"

Even if we could clarify some of the ambiguity, there's the question of whether scientists actually say we should trust scientists.  If some scientists do not make that claim, them the initial premise is false rendering the conclusion false.

Statement 2 correctly (in my view) recognizes statement 1 to be an appeal to authority or an appeal to an anonymous authority.

There seems to be an implication between statement 2 and the conclusion ... perhaps the implication is that appeals to authority don't by themselves justify trusting a source.  Still there is an unbridged chasm between the claim of an appeal to authority and refusing to trust any scientist, regardless of whether the first premise is true or false.