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Question
Write scientific reason.
The third period contains only eight elements even though the electron capacity of the third shell is 18
Solution
The third period contains only eight elements even though the electron capacity of the third shell is 18 because there are 10 electrons which are found to have higher energy than the remaining 8 electrons. The universe prefers the path of less energy. The energy of these 10 electrons is equivalent to the energy of the 4th shell electron. That’s why these electrons are not counted in 3rd shell.
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