Identify the last element from the fifth period.
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. Xenon.
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The fifth period of the periodic table contains 18 elements (from Rubidium, Rb (37) to Xenon, Xe (54)).
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Xenon (Xe), a noble gas with atomic number 54, is the last element in this period.
Other Options:
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Helium (He): First noble gas (Period 1).
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Yttrium (Y): Transition metal (Period 5, but not the last).
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Rubidium (Rb): First element of Period 5.