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An atom of element X has one more shell of electrons than an atom of beryllium, but it has one less valence electron than beryllium. Which element is element X?

sodium (Na)
boron
b. magnesium (Mg)
lithium (Li)

2 Answers

2 votes

The answer is C (magnesium (Mg)


User Jwvh
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mg magnesium becuase one period down and one group to the side

User Katone Vi
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