Which one of the following species does not exist under normal conditions ?

Step-by-step solution

Key Idea Molecules with zero bond order, do not exist. (a) Be ₂⁺(4+4-1=7)= aligned & 1 ~s ^2, 1 ~s ^2, 2 ~s ^2, 2 ~s ^1 & BO = 4-3 2 =0.5 aligned (b) Be ₂(4+4=8)= 1 ~s ^2, 1 ~s ^2, 2 ~s ^2, 2 ~s ^2 BO = 4-4 2 =0 (c) B ₂(5+5=10) gathered = 1 ~s ^2, 1 ~s ^2, 2 ~s ^2, 2 ~s ^2, 2 p_ x ^1 2 p _ y ^1 BO = 6-4 2 =1 gathered (d) aligned & Li ₂(3+3=6) & = 1 ~s ^2, 1 ~s ^2, 2 ~s ^2 & = 4-2 2 =1 aligned BO = 4-2 2 =1 Thus, Be ₂ does not exist under normal conditions.