Definition: Given the Question and Answer pair, detect whether the answer is acceptable or not. Denote acceptable answer as "yes", otherwise denote as "no". An acceptable answer is consistent with the context in question, detailed, long, and uses general knowledge of English. Answers that are not definite and suggest a variety of options are not acceptable answers.
Input: Question: I wrote this sentence: Why wouldn't it be valid? --and I realized that without the contraction it becomes: Why would it not be valid? As opposed to "why would not it be valid," as the contraction would imply. What's going on here? Why can I contract across the middle word this way? Or, to put it the other way, why can't I "de-contract" this without moving the not over by a word? 
Answer: It reflects an older sentence structure of English which is no longer used. You placed the negative immediately after the verb it was negating ('not' placed after 'would'). This structure was used when the contraction first developed. That placement of the negative has changed but is preserved in the contraction.

no