Modern Periodic Table — Chemistry STD 11 Science — Question
Maharashtra BoardEnglish MediumSTD 11 ScienceChemistryModern Periodic Table2 Marks
Question
How many elements are present in the $6^{th}$ period? Explain.
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Answer
The $6^{th}$ period begins by filling the last electron in the subshell $‘6s \ ’$ and ends by completing the subshell $‘6p \ ’.$ Therefore, the sixth period has the subshells filled in increasing order of energy as $6s < 4f < 5d < 6p.$
The electron capacities of these subshells are $2, 14, 10 \ and \ 6,$ respectively. Therefore, the total number of elements in the $6^{th}$ period is $2 + 14 + 10 + 6 = 32.$
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