Answer:
"The elements are arranged in seven horizontal rows,called periods or series,and 18 vertical columns,called Groups."
Explanation:
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Answer:
[H₃O⁺] = 7.08×10⁻⁹ M
Explanation:
pH = - log [H₃O⁺]
[H₃O⁺] = 10^⁻pH
Therefore, [H₃O⁺] = 10⁻⁸¨¹⁵
[H₃O⁺] = 7.08×10⁻⁹ M
The answer you are looking for is A. the average atomic mass hope this helped have a nice day :)