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Question: Answered & Verified by Expert
An element with atomic number 20 will be placed in which period of the periodic table
ChemistryClassification of Elements and Periodicity in PropertiesJEE Main
Options:
  • A 4
  • B 3
  • C 2
  • D 1
Solution:
2924 Upvotes Verified Answer
The correct answer is: 4
$1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^2$ principal quantum no. is 4 so it belongs to $4^{\text {th }}$ period.

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