Question

which pair of elements could A & B be
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Answer 1

Answer:

a is oxygen and b is flourine

Explanation:

here a is Oxygen and b fluorine because a is having 7 electrons in its outermostshell and it requires one electron to complete its octate so 2 + 7 will be equal to 9 and the element on the 9th is fluorine and a will be oxygen because b is having 6 in its outer most shell so as b is having 8 will be equal to 8 and the element having it is oxygen