Look at the diagrams below, showing mystery element A and mystery element D. How many valence electrons does mystery element A contain? Based on this, would
it want to gain or lose electrons? Why is this? How many valence electrons does
mystery element D have? Based on this, would it want to gain or lose electrons?
Why is this?
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D
^ K12

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.