Question

d) Species which do not exist
do not exist on the earth
now.​

Answer 1

dinosaurus, dodo bird , Phoenix bird etc...

Answer 2

Explanation:

Be

2

does not exist under normal condition. Beryllium has four electrons , so electronic configuration of Be

2

having 8 electrons will be σ1s

2

σ

∗

1s

2

σ2s

2

σ

∗

2s

2

and the bond order is

2

N

a

−N

b

=0

Since Be

2

is having bond order 0 , no bond is formed between the two atoms. Hence Be

2

is unstable