Chemistry: Molecular Orbital Electronic Configs.

[thepassenger48]

Hi,
I'm having a lot of trouble with the following question.

Write molecular orbital electronic configurations for each of the species listed below. Calculate the bond order in each case.

a) B2-

...

Answer:
(σ1s)2 (σ*1s)2 (σ2s)2 (σ*2s)2 (π2py)2 (π2pz)1



If anyone can tell me how to obtain this answer, I would be very happy.
Thanks.

 

[TeethWhitener]

This is simply an issue of setting up the proper MO diagram. Here's one for neutral B₂:
http://img.sparknotes.com/figures/8/83ce1fb7be648ede5785ea60c96b495c/b2correlate.gif
B₂^- will just have an extra electron in the lowest available orbital.