Question

Find the odd one out: Helium; Radium; Radon; Krypton.​

Answer 1

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The odd one is Radium

Because the other three elements are noble gases but it is not.

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Answer 2

Answer:

Helium

Explanation:

Helium because it is an noble gas ( inert gas )

Radium; Radon; Krypton are radiactive metals