Final answer:
The first letter that stands alone as the symbol of a chemical element alphabetically is B, which represents Boron.
Step-by-step explanation:
Alphabetically, the first letter that stands alone as the symbol of a chemical element is B, which represents Boron. In the periodic table, symbols of elements are arranged according to atomic number rather than alphabetically. However, when we arrange these symbols alphabetically, B for Boron is the first letter that stands alone representing a single element.
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