Periodic Classification and Periodic Properties 2 Question 12
12. Identify the least stable ion amongst the following.
(a) $\mathrm{Li}^{+}$
(b) $\mathrm{Be}^{-}$
(c) $\mathrm{B}^{-}$
(d) $\mathrm{C}^{-}$
(2002, 3M)
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Answer:
Correct Answer: 12. (b)
Solution:
- $\mathrm{Be}^{-}$is the least stable ion, $\mathrm{Be}\left(1 s^{2} 2 s^{2}\right)$ has stable electronic configuration, addition of electron decreases stability.
