Which element, represented by X, reacts with fluorine to produce the compound XF2?
(1) aluminum (3) magnesium
(2) argon (4) sodium



Answer :

The answer is (3) magnesium. Aluminum usually has valence of +3 and Sodium usually has valence of +1. Argon is usually not react with others. Because it is already stable with 8 electrons at the outer shell.

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