The electronic configuration of an element 'X' is 2,8,8,2. To which (a) period and (b) group of the modem periodic table does 'X' belong ? State its valency. Justify your answer in each case.
(a) 4th period, because it has four shells.(b) 2nd group, because it has two valence electrons. It will show valency of 2 (or+2) because it will ' lose two electrons to become stable