Question

An element M has an atomic number 9 and atomic mass 19. Its ion will be represented by

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

Answer 1

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

Z=9 Z=9, thus the ground state electron configuration is 1s 2s2 2p51s22s22p5. It needs one more electron to attain stable electron configuration of Neon.

So the ion will be M-.
Neeomn. Thus, its ion is M−MSo