The molecular energies an be arranged as _____________
Answers
Explanation:
Molecular Orbital Theory (MOT)=: Molecular Orbital Theory (MOT) was developed by F. Hund and R.S
Muliken in 1932. Main postulates of this theory are:
1. Atomic orbitals of comparable energy and proper symmetry combine together to form molecular orbitals.
2. The moment of electrons in a molecular orbitals is influenced by all the nuclei of combining atoms.
3. The number of molecular orbitals formed is equal to the number of combining atomic orbitals. When atomic orbitals (AO's) combine together two molecule orbitals (MO's) are formed.,One molecule orbitals possesses higher energy than corresponding atomic orbitals and is called anti bonding molecular orbital (ABMO) and the other has lower and is called bonding molecular orbital (BMO).
4. In molecules, electrons are present in molecular orbitals. The electrons filling is in accordance with Pauli's exclusion principle. Aufbau principle and Hund's rule
The molecular orbital configuration of O
2
,O
2
−
,O
2
2−
and O
2
+
are as follows:
O
2
=σ1s
2
,σ∗1s
2
,σ2s
2
,σ∗2s
2
,σ2p
z
2
,π2p
x
2
=π2p
y
2
,π∗2p
x
1
=π∗2p
y
1
Bond order =
2
10−6
=
2
4
=2
O
2
−
=σ1s
2
,σ∗1s
2
,σ2s
2
,σ∗2s
2
,σ2p
z
2
,π2p
x
2
=π2p
y
2
,π∗2p
x
2
=π∗2p
y
1
Bond order =
2
10−7
=
2
3
=1.5
O
2
2−
=σ1s
2
,σ∗1s
2
,σ2s
2
,σ∗2p
z
2
,π2p
x
2
=π2p
y
2
,π∗2p
x
2
,=π∗2p
y
2
Bond order =
2
10−8
=
2
2
=1.0
O
2
+
=σ1s
2
,σ∗1s
2
,σ2s
2
,σ∗2s
2
,σ2p
z
2
,σ2p
x
2
Bond order =(10−5)/2=5/2=2.5
The bond order decreases in the order is
O
2+
>O
2
>O
2
−
>O
2
2−
As we know that stability is directly proportional to bond order.
Hence, increasing order of stability is:
O
2
2−
<O
2
−
<O
2
<O
2
+