Question

An element $M$ has an atomic mass of $19$ and atomic number $9$, its ions is represented by

• A. $M^{+}$
• B. $M^{2+}$
• C. $M^{-}$
• D. $M^{2-}$

Answer 1

Answer: (C)

Configuration of an element ${}_{9}M=1s^2,2s^2,2p^5$.
Hence, its ion will be $M^{-}$ because it can easily gain one electron to have octet.