Exchange energy

Exchange energy
https://www.youtube.com/watch?v=bT5rL_hERpY

1. Concept of Exchange energy
(E
ex)
Dr. MithilFalDesai
Shree Mallikarjun and Shri Chetan Manju Desai College
Canacona Goa

2. Relative energies of atomic orbitals
1s
2s
2p
3d
3s
3p
Z<20
Z>20
Energy
4s
4p
4d
4f

3. Electronic configurations of the atoms
Atomic Number Name Symbol Orbitals Shells
1 Hydrogen H 1s
1
1
2 Helium He 1s
2
2
3 Lithium Li [He] 2s
1
2,1
4 Beryllium Be [He] 2s
2
2,2
5 Boron B [He] 2s
2, 2p
1 2,3
6 Carbon C [He] 2s
2, 2p
2 2,4
7 Nitrogen N [He] 2s
2
, 2p
3
2,5
8 Oxygen O [He] 2s
2
, 2p
4
2,6
9 Fluorine F [He] 2s
2
, 2p
5
2,7
10 Neon Ne [He] 2s
2
, 2p
6
2,8
11 Sodium Na [Ne] 3s
1
2,8,1
12 Magnesium Mg [Ne] 3s
2
2,8,2
13 Aluminum Al [Ne] 3s
2
, 3p
1
2,8,3
14 Silicon Si [Ne] 3s
2, 3p
2 2,8,4
15 Phosphorus P [Ne] 3s
2
, 3p
3
2,8,5
16 Sulfur S [Ne] 3s
2
, 3p
4
2,8,6
17 Chlorine Cl [Ne] 3s
2
, 3p
5
2,8,7
18 Argon Ar [Ne] 3s
2
, 3p
6
2,8,8
19 Potassium K [Ar] 4s
1
2,8,8,1
20 Calcium Ca [Ar] 4s
2
2,8,8,2
21 Scandium Sc [Ar] 3d
1
, 4s
2
2,8,9,2
22 Titanium Ti [Ar] 3d
2, 4s
2 2,8,10,2
23 Vanadium V [Ar] 3d
3, 4s
2 2,8,11,2
24 Chromium Cr [Ar] 3d
5
, 4s
1
2,8,13,1
25 Manganese Mn [Ar] 3d
5
, 4s
2
2,8,13,2
26 Iron Fe [Ar] 3d
6
, 4s
2
2,8,14,2
27 Cobalt Co [Ar] 3d
7
, 4s
2
2,8,15,2
28 Nickel Ni [Ar] 3d
8
, 4s
2
2,8,16,2
29 Copper Cu [Ar] 3d
10
, 4s
1
2,8,18,1
30 Zinc Zn [Ar] 3d
10, 4s
2 2,8,18,2
Anomalous electronic configurations

4. Anomalous electronic configurations
Atomic
Number NameSymbol Orbitals
24 ChromiumCr[Ar] 3d
5
, 4s
1
29 Copper Cu[Ar] 3d
10
, 4s
1
More stable
Exchange energy (E
ex)

5. Exchange energy (E
ex)
??????
????????????=෍
??????(??????−1)
2
??????
Nitrogen[He] 2s
2
, 2p
3
2p
x2p
y2p
z 2p
x2p
y2p
z
N-number of electrons with parallel spin
K-constant
or
Electronscanexchangetheirposition
withotherelectronshavingparallelspin.

6. Exchange energy (E
ex)
??????
????????????=෍
??????(??????−1)
2
??????
2p
x2p
y2p
z 2p
x2p
y2p
z
N-number of electrons with parallel spin
K-constant
or
Electronscanexchangetheirposition
withotherelectronshavingparallelspin.
Nitrogen[He] 2s
2
, 2p
3

7. ??????
????????????=෍
3(3−1)
2
??????
=3K
??????
????????????=෍
2(2−1)
2
??????
=1K
Exchange energy (E
ex)
??????
????????????=෍
??????(??????−1)
2
??????
N-number of electrons with parallel spin
K-constant
2p
x2p
y2p
z 2p
x2p
y2p
z
orNitrogen[He] 2s
2
, 2p
3