Q. The element, with atomic number , will be

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Solution:

Electronic configuration of element with atomic number will be . Since its electronic configuration in the outer most orbit resemble with that of inert or noble gases, therefore it will be noble gas element. The inert gas radon has atomic number . When we add electrons to it, we get the element with atomic number . In seventh period, a maximum of electrons can be accommodated. Hence, element with atomic number is a noble gas.