Question

Molecular Orbital Theory -- Homodiatomics Use the molecular orbital model to fully describe the bonding in O2+, O2, O2-, and O22-. Determine which of the following statements are true and which are false.

The electron configuration of O2- is (σ2s)2(σ2s*)2(σ2p)2(π2p)4(π2p*)

The electron configuration of O2+ is (σ2s)2(σ2s*)2(σ2p)2(π2p)4(π2p*)

The number of unpaired electrons in O2+ and O22- is, respectively, 1 and 2.

The bond lengths increase in the order: O2+ < O2 < O2- < O22-.

The bond order in O2+ and O2 is, respectively, 2.5 and 2.

Bond length and bond energy both increase with increasing bond order.

Answer 1

molecular orbital for oxygen molecule:

Each oxygen atom has 8 electrons, toata=16 electrons,

these are arranged in 61s²,6*1s²,62s²,6*2s²,62p²x,pi2p²y,pi2p²z,pi*2p¹y,pi*2p¹z (6=sigma)

bond order=no. of electrons occupying bonding orbital-no. of electrons occupying non-bonding orbital/2,

=10-6=4/2=2,

bond order of oxygen MOLECULE(O2)=2,

AS shown in molecular orbital for oxygen molecule we can draw the molecular orbital for O2-,O2+,O2^2-,

FOR O2+ The toal electrons=15 (8+7),

bond order=10-5/2=5/2=2.5,

for O2-, the total electrons =17(8+9),

bond order=10-7=3/2=1.5,

for O22-= TOTAL Electron=18 (8+10),

bond order=10-8=2/2=1,

from that no. of unpaired electrons i O2+=1 IS TRUE, BUT NO. OF UNPAIRED ELECTRONS IN O22-=2 IS FALSE , AS THERE ARE NO UNPAIRED ELECTRONS IN O22-..BOND LENGTH INCRESES IN THE ORDER GIVEN IS FALSE. THECORRECT ORDER=O2+>O2>O2->O22- SEE TABOVE (CALCULATED BOND ORDER).

THE BOND ORDER FOR O2+=2.5 and for O2 =2 is true,

last statement is false, correct is as the bond order increases bond length decreses and energy increases.

correct electronidc confi. of o2-= 61s²,6*1s²,62s²,6*2s²,62p²x,pi2p²y,pi2p²z,pi*2p²y,pi*2p¹z ,

correct electronidc confi. of o2+= 61s²,6*1s²,62s²,6*2s²,62p²x,pi2p²y,pi2p²z,pi*2p²y,pi*2pz ,