NCERT Exercise 3.27 - Classification of Elements and Periodicity in Properties
Question: Use the periodic table to identify: (a) an element with five outer-subshell electrons, (b) one tending to lose two electrons, (c) one tending to gain two electrons, (d) a group containing metal, non-metal, liquid and gas at room temperature.
Answer: (a) N or P (ns2np3); (b) Mg or Ca; (c) O or S; (d) Group 17.
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