WBJEE 2020 Chemistry Solved Paper

Species :He22+(2)
Electronic Configuration: 1s21s0
Bonding electrons =2
Anti bonding electrons=0
Bondorder = 2 - 0 / 2 = 1

Species : He2
Electronic Configuration: 1s2
Bonding electrons : 2
Anti bonding electrons : 2
Bond order = no . of bonding - no of anti bonding/2
= 2-2 /2 = 0

The electrons distribution in molecular orbitals is 1s2,2s1
B.O=‌

2−1

2

=‌

1

2

=0.5