Which one of the following anions is least stable?

CONCEPT:

Stability of Anions

• The stability of anions depends on various factors, including:
  • The electronegativity of the atom carrying the negative charge.
  • The ability of the atom to delocalize the negative charge (resonance effects).
  • The size of the atom: Larger atoms can better accommodate negative charge due to lower charge density.
• Electronegativity is a key factor because more electronegative atoms are better able to stabilize negative charges.
• In this case, we compare the stability of the anions: Be⊖, Li⊖, B⊖, and C⊖.

EXPLANATION:

• Be (Beryllium) is the least electronegative element among the given options. It has the lowest ability to stabilize a negative charge.
• Li (Lithium) is slightly more electronegative than Be, so the Li⊖ anion is slightly more stable than Be⊖.
• B (Boron) is more electronegative than both Be and Li, so the B⊖ anion is more stable than Be⊖ and Li⊖.
• C (Carbon) is the most electronegative among the given options, so the C⊖ anion is the most stable of all.
• As a result, the Be⊖ anion is the least stable because Beryllium is the least electronegative and the least able to stabilize the negative charge.

Therefore, the correct answer is Option 1: Be⊖.