From the original question, I understood it as:
If A, then B
Where B is the logical and necessary result of A.
In that construction, the Hebrew אם is followed by a waw followed by the conclusion.
However, in Biblical Hebrew, אם is used in constructs other than the above.
It is used in a compound lexeme:
The compound lexeme כי אם found in over 150 verses, has the meaning of “except” or “unless”, though it has no exact equivalent in English.
The compound lexeme עד אם found in four verses, meaning “until”.
It’s also used in ways not strictly as “if”:
Genesis 4:7 “Should not you do well? Bear up. And should you not do well, …”
Genesis 13:16 “…should a person be able to number … even …”
Genesis 20:7 “…and should you not be causing to return…”
Used in incomplete sentences:
Genesis 18:21 “…and if not…? I intend to know.”
This question is a perfect example of how one cannot say that each word has one word translation in English—the closest word in English to אם is “if”, but אם has a broader range of semantic meaning than does “if” and a translator should take that into account.
My original answer dealt with the “if A then B” question, but I see that other responses brought in these other considerations as well.
Karl W. Randolph.