Question

A element $M$ has an atomic mass $19u$ and atomic number is $9$, the most stable ionic form of the element is:

• A. $M^{+}$
• B. $M^{2+}$
• C. $M^{-}$
• D. $M^{7-}$

Answer 1

The correct option is C $M^{-}$

The electronic arrangement of the element will be $2,7$.
Since the element has seven electron in its outermost orbital, so it always tends to accept an electron so as to acquire the stable noble gas configuration.
So its ionic species will be $M^{-}$.