Nuclear chemistry B.Sc.III

Inorganic Chemistry

1. Nuclear Chemistry
Introduction: -
The study of the nuclear changes in an atom is termed as nuclear
chemistry. Nuclear changes are source of radioactivity & nuclear power. That’s
why nuclear chemistry is very important branch of chemistry.
The process in which atom of one element is converted into atom of
another element is called transmutation. Transmutation may take place
naturally or brought about artificially.
uncontrollable disintegration occurs by emission of active radiations from an
unstable atomic nucleus
radiations is called radioactive substance.

Nuclear Reaction: -
The reaction in which the nucl
called nuclear reaction.
According to Bethe above reaction can be represented as
i.e. Target element (Projectile, Emission) Daughter element.
* The particle used for bombardment in nuclear reaction is called Projectile.
* The element which is bombarded by Projectile is called Target element.
* The product obtained in nuclear reaction is called R
element.
* The particle emitted during

Energetic of Nuclear Reaction
loss of energy.
Nuclear Reaction in which energy i
reaction.
Nuclear Chemistry Prof. Jadhav Swapnil S.
The study of the nuclear changes in an atom is termed as nuclear
Nuclear changes are source of radioactivity & nuclear power. That’s
nuclear chemistry is very important branch of chemistry.
The process in which atom of one element is converted into atom of
another element is called transmutation. Transmutation may take place
naturally or brought about artificially. Phenomenon of sponta
uncontrollable disintegration occurs by emission of active radiations from an
is called radioactivity. The substance that emits
called radioactive substance.
he reaction in which the nucleus of an atom undergoes transmutation is
According to Bethe above reaction can be represented as
9
Be (α, n)
i.e. Target element (Projectile, Emission) Daughter element.
used for bombardment in nuclear reaction is called Projectile.
is bombarded by Projectile is called Target element.
in nuclear reaction is called Recoil nucleus or Daughter
ring nuclear reaction is called Emission.
Energetic of Nuclear Reaction: - Nuclear Reactions associat
Nuclear Reaction in which energy is absorbed is called endoergic n
Prof. Jadhav Swapnil S.
The study of the nuclear changes in an atom is termed as nuclear
Nuclear changes are source of radioactivity & nuclear power. That’s

The process in which atom of one element is converted into atom of
another element is called transmutation. Transmutation may take place
henomenon of spontaneous and
uncontrollable disintegration occurs by emission of active radiations from an
is called radioactivity. The substance that emits
ergoes transmutation is

Be (α, n)
12
C.
i.e. Target element (Projectile, Emission) Daughter element.
used for bombardment in nuclear reaction is called Projectile.
is bombarded by Projectile is called Target element.
ecoil nucleus or Daughter
nuclear reaction is called Emission.

Nuclear Reactions associated with gain or
s absorbed is called endoergic nuclear

2. Nuclear Reaction in which energy
reaction.
In Nuclear Reaction change in energy is large and calculated by Einstein
equation. E = m C
2

1 amu = 931 MeV 1 MeV = 9.648 × 10

Types of Nuclear Reaction:
1) Artificial Transmutation 2) Natural Transmutation
1) Artificial Transmutation
i) Artificial Transmutation or Artificial disintegration:
When the transmutation is done by artificial means is called Artificial
Transmutation or disintegration.
Or the conversion of one element into another element by artificial means is
called Artificial Transmutation or disintegration.
First Artificial Transmutation was recognized, described and reported by
Rutherford in 1919.
E.g. Using various projectiles
Nuclear Reaction in which energy is released is called exoergic n
In Nuclear Reaction change in energy is large and calculated by Einstein
1 amu = 931 MeV 1 MeV = 9.648 × 10
7
KJ/mol
Types of Nuclear Reaction: -
1) Artificial Transmutation 2) Natural Transmutation
1) Artificial Transmutation
i) Artificial Transmutation or Artificial disintegration: -
When the transmutation is done by artificial means is called Artificial
ransmutation or disintegration.
the conversion of one element into another element by artificial means is
called Artificial Transmutation or disintegration.
First Artificial Transmutation was recognized, described and reported by
projectiles various transmutations are carried out
is released is called exoergic nuclear

In Nuclear Reaction change in energy is large and calculated by Einstein

When the transmutation is done by artificial means is called Artificial
the conversion of one element into another element by artificial means is

First Artificial Transmutation was recognized, described and reported by
transmutations are carried out as

3. ii) Artificial radioactivity or induced radioactivity:
The radioactivity produced by process of artificial atomic transmutation
is called artificial radioactivity or induced radioactivity.
Artificial radioactivity first discovered by Irene Curie
husband F. Joliot awarded by Nobel
e.g. The bombardment of α particle on Aluminium forms rad ioactive
Phosphorous which emits po
“The process of converting stable nuclei into unstable radioactive nuclei
by artificial transmutation is called artificial radioactivity.”
e.g.

iii) Projectile capture reaction:
The Nuclear Reaction in which the projectile is captured with
γ emission is called Projectile
The Projectile captured is usually neutron but for low masses nuclei proton is
also captured.
ii) Artificial radioactivity or induced radioactivity: -
The radioactivity produced by process of artificial atomic transmutation
radioactivity or induced radioactivity.
Artificial radioactivity first discovered by Irene Curie
husband F. Joliot awarded by Nobel Prize in 1935.
he bombardment of α particle on Aluminium forms rad ioactive
Phosphorous which emits positron to form Silicon.
process of converting stable nuclei into unstable radioactive nuclei
by artificial transmutation is called artificial radioactivity.”
iii) Projectile capture reaction: -
The Nuclear Reaction in which the projectile is captured with
called Projectile capture reaction.
The Projectile captured is usually neutron but for low masses nuclei proton is
The radioactivity produced by process of artificial atomic transmutation
Artificial radioactivity first discovered by Irene Curie-Joliot and her
he bombardment of α particle on Aluminium forms rad ioactive

process of converting stable nuclei into unstable radioactive nuclei

The Nuclear Reaction in which the projectile is captured with or without
The Projectile captured is usually neutron but for low masses nuclei proton is

4. iv) Projectile capture particle emission reaction:
The Nuclear Reaction in which the projectile is captured
another particle is called Projectile capture particle emission reaction.
Majority of nuclear reactions are come under this category.

v) Nuclear fission reaction:
a) The reaction in which heavy nucleus is broken down into two or more nuclei
having medium masses with liberation of large
nuclear fission reaction.
b) When the nuclei with mass no. greater than 200 are bomba
or other projectile with sufficient energy
c) Fission reaction usually accompanied by neutrons.
d) First nuclear reaction discovered by German scientist Otto
Strassman in 1938.

e) During fission reaction 2
which bring breaking of
chain reaction. (The chain reaction which continued without break is called
sustained or self propagated reaction.)
released.
capture particle emission reaction: -
The Nuclear Reaction in which the projectile is captured
another particle is called Projectile capture particle emission reaction.
Majority of nuclear reactions are come under this category.
Nuclear fission reaction: -
a) The reaction in which heavy nucleus is broken down into two or more nuclei
having medium masses with liberation of large amount of
b) When the nuclei with mass no. greater than 200 are bomba
or other projectile with sufficient energy undergoes fission process.
c) Fission reaction usually accompanied by neutrons.
First nuclear reaction discovered by German scientist Otto
reaction 2-3 neutrons are emitted called seco
next target nuclei and reaction is continued called
chain reaction. (The chain reaction which continued without break is called
sustained or self propagated reaction.). Due to this large am
The Nuclear Reaction in which the projectile is captured with emission of
another particle is called Projectile capture particle emission reaction.

a) The reaction in which heavy nucleus is broken down into two or more nuclei
amount of energy is called
b) When the nuclei with mass no. greater than 200 are bombarded by neutron
undergoes fission process.


First nuclear reaction discovered by German scientist Otto-Hahn and F.

3 neutrons are emitted called secondary neutrons
and reaction is continued called
chain reaction. (The chain reaction which continued without break is called
. Due to this large amount of energy is

5. f) The pair of fission product are classified as
And ii) heavier nuclei (Z = 130
g) Atom bomb works on the principal of fission reaction.
h) Energy produced in fission of 1 g U
of coal (8.22 × 10
7
KJ)

vi) Nuclear Fusion: -
a) The reaction in which two or more light nuclei fuse to form stable heavier
nucleus with liberation of very large energy is called nuclear fusion reaction.
b) The energy release during fus
reaction.
c) Fusion reaction takes
pressure hence called as thermonuclear reaction.
d) According to Bethe energy of sun where tem
by the proton-proton cycle as
f) The pair of fission product are classified as- i) lighter nuclei (Z = 80
nuclei (Z = 130-150)
bomb works on the principal of fission reaction.
h) Energy produced in fission of 1 g U-235 is equal to burning of 2.5 metric tons
a) The reaction in which two or more light nuclei fuse to form stable heavier
nucleus with liberation of very large energy is called nuclear fusion reaction.
release during fusion reaction is four times greater than fission
place at high temperature (4 × 10
pressure hence called as thermonuclear reaction.
d) According to Bethe energy of sun where temperature is 2 × 10
proton cycle as-

i) lighter nuclei (Z = 80-100)
equal to burning of 2.5 metric tons
a) The reaction in which two or more light nuclei fuse to form stable heavier
nucleus with liberation of very large energy is called nuclear fusion reaction.

greater than fission
place at high temperature (4 × 10
6

0
c) and high
perature is 2 × 10
7
k is generated

6. e) Fusion reaction are not suitable for man
f) Hydrogen bomb works on the principal of fusion reaction.

* Use of Uranium, Thorium and Plutonium for atomic
reactor: -
The energy released during nuclear reaction used for mankind is known
as atomic or nuclear energy. The cost of nuclear energy is comparable or even
less than traditional source. It has comparatively less pollution.
1. Thorium is used as blanket as it is fertile material (
the reactor atomic transmutation take place to form fissionable product as
2.
233
U and
235
U are fissionable nuclides.
3. Plutonium is not occurring n
natural uranium.
Thus
233
U,
235
U and
239
Pu are fissile and used atomic fuel.
e) Fusion reaction are not suitable for man-made experimentation.
f) Hydrogen bomb works on the principal of fusion reaction.
Note:
Use of Uranium, Thorium and Plutonium for atomic energy in nuclear
The energy released during nuclear reaction used for mankind is known
as atomic or nuclear energy. The cost of nuclear energy is comparable or even
less than traditional source. It has comparatively less pollution.
is used as blanket as it is fertile material (do not undergo fission
the reactor atomic transmutation take place to form fissionable product as
U are fissionable nuclides.
233
U is obtained from
232
3. Plutonium is not occurring naturally. The fissile Plutonium obtained from
Pu are fissile and used atomic fuel.

made experimentation.


energy in nuclear
The energy released during nuclear reaction used for mankind is known
as atomic or nuclear energy. The cost of nuclear energy is comparable or even
less than traditional source. It has comparatively less pollution.
do not undergo fission). In
the reactor atomic transmutation take place to form fissionable product as

232
Th.
aturally. The fissile Plutonium obtained from

7. * Typical power reactor
fuel, Moderator, Control road, Coolant.
Nuclear fuel:-
233
U,
235
U and
Moderator: - Moderators are used to slow down the fission neutrons. They are
made up of light elements and their compounds.
E.g. Heavy water, Paraffin, Beryllium, G
Control road: - Control rods are bars of metal such as cadmium, Boron. They
absorb neutrons and control the chain reaction.
Coolant: - Coolants are heat transfer agents. They transfer heat energy to heat
exchanger. E.g. liquid Sodium metal, CO
polyphenyls etc.
Shield or protective Chamber
components of reactor are enclosed in a chamber to avoid leaking of nuclear
radiations.

Atom Bomb: -
The basic condition for nuclear explosion
energetic neutron. The neutron production factor
Nuclear fission occurs when k>1, when k = 1 there is controlled chain
reaction. The efficiency of nuclear fission depends on weight and volume of
nuclear fuel used. The optimum size of the fuel at which the chain reaction
becomes self sustained is called critical size. (
mass). At subcritical mass,
fuel is less than critical mass i
more than critical mass is called over or super critical mass.
Typical power reactor: - The main components of the reactor are Nuclear
fuel, Moderator, Control road, Coolant.
U and
239
Pu are generally used as a fuel in power reactor.
Moderators are used to slow down the fission neutrons. They are
made up of light elements and their compounds.
Heavy water, Paraffin, Beryllium, Graphite etc.
Control rods are bars of metal such as cadmium, Boron. They
control the chain reaction.
Coolants are heat transfer agents. They transfer heat energy to heat
exchanger. E.g. liquid Sodium metal, CO2 gas, water, Heavy water air,
Shield or protective Chamber: - It is made up of cement and concrete. The
components of reactor are enclosed in a chamber to avoid leaking of nuclear
The basic condition for nuclear explosion is generation of highly
energetic neutron. The neutron production factor (k) is given by
Nuclear fission occurs when k>1, when k = 1 there is controlled chain
reaction. The efficiency of nuclear fission depends on weight and volume of
used. The optimum size of the fuel at which the chain reaction
becomes self sustained is called critical size. (And the mass is called critical
, k < 1 while at super critical mass, k > 1.
fuel is less than critical mass is called subcritical mass.)(The mass of fuel is
more than critical mass is called over or super critical mass.)
The main components of the reactor are Nuclear
Pu are generally used as a fuel in power reactor.
Moderators are used to slow down the fission neutrons. They are
Control rods are bars of metal such as cadmium, Boron. They
Coolants are heat transfer agents. They transfer heat energy to heat
Heavy water air,
It is made up of cement and concrete. The
components of reactor are enclosed in a chamber to avoid leaking of nuclear

is generation of highly
(k) is given by

Nuclear fission occurs when k>1, when k = 1 there is controlled chain
reaction. The efficiency of nuclear fission depends on weight and volume of
used. The optimum size of the fuel at which the chain reaction
the mass is called critical
t super critical mass, k > 1. (The mass of
The mass of fuel is

8. For nuclear explosion over critical and subcritical assembly is essential. It
is carried out by two techniques.
1. Assembling two subcritical m
quickly as possible.
2. Subcritical masses of fuel are subjected to high pressure
fuel increases, surface area decreases and thus rate of neutron production
accelerated leading to explosion.
* Schematic diagram for probable assembly for atom bomb:
It consist two subcritical masses
One is target while other one is projectile. The projectile is embedded in
explosive material like trinitrotoluene (TNT).
drives projectile
235
U into target
result instantaneous chain reaction start
For nuclear explosion over critical and subcritical assembly is essential. It
is carried out by two techniques.
1. Assembling two subcritical masses of fuel into an over critical mass as
masses of fuel are subjected to high pressure thereby density of
fuel increases, surface area decreases and thus rate of neutron production
accelerated leading to explosion.
diagram for probable assembly for atom bomb:
subcritical masses of pure
235
U at two ends of gun barrel.
One is target while other one is projectile. The projectile is embedded in
explosive material like trinitrotoluene (TNT). When the TNT is detonating, it
U into target
235
U. A supercritical mass is obtained
chain reaction start and the bomb explode.
For nuclear explosion over critical and subcritical assembly is essential. It
asses of fuel into an over critical mass as
thereby density of
fuel increases, surface area decreases and thus rate of neutron production
diagram for probable assembly for atom bomb: -

U at two ends of gun barrel.
One is target while other one is projectile. The projectile is embedded in
When the TNT is detonating, it
U. A supercritical mass is obtained. As a
explode.

9. Applications of Radioisotopes as tracers:-
1) Chemical investigation (Esterification): -
In ester hydrolysis by using water enriched in O
18
isotope, it is found that
the acid only contains excess O
18
as,
R--CO—OR’ + HO
18
H R--CO—O
18
H + R’—OH
This indicates that, -OR' bond is broken and O
18
H from H 2O
18
takes the place of —
OR
’
while H combine with —OR’ producing alcohol.

2) Structural determination of PCl
5: -
1. The position of 5 chlorine atom in PCl
5 is determined by isotopic labelling
method.
2. First PCl
5 is synthesized by PCl3 and isotopic Cl2 (
36
Cl2) and then hydrolysed.
i) PCl3 + 36Cl2
*


PCl5
*
ii) PCl5
*
+ H2O POCl 3 + 2HCl
*

3. The reaction shows isotopic Cl
*
atoms are remain in HCl and not in POCl3
which indicates in PCl
5, two Cl atoms occupy different position than remaining
three Cl atoms.
4. Thus, in PCl
5 3-Cl atoms are at equatorial plane and 2-Cl atoms are at
vertices.
5. This evidence confirms the Structural of PCl
5 is trigonal bipyramidal.


3) Medical Application: - (Isotopic dilution method for determination of
volume of blood)
(a) Volume of blood can be determined by using isotopic dilution method. (b)
1 cm
3
of blood of patient is withdraw and labelled with solution of
24
Na as NaCl
and its initial specific activity (S
1) is measured in 0.1 cm
3
. The remaining
labelled sample is reinserted (0.9 cm
3
= y). (c) After 15 minutes once again 1
cm
3
of blood of patient is withdraw and its initial specific activity (S 2) is
measured. (d) The unknown volume of blood (x) in patient body is then
determined as- y S
1 = (x + y) S2 but, y << x i.e x + y = x
y S
1 = x S2 x =
T
h
y cm
3

* Normal adult human being may have about 5 to 6 litres of blood.

10. (D) Carbon dating: - (W. F. Libby (1960) first developed this technique.)
The process of determining the age of historic and archaeological
organic samples by comparing the ratio of
14
C to
12
C is called
14
C dating or
carbon dating.
The isotope
14
C is radioactive. The
14
C atom is produced in upper atmosphere
by the bombardment of neutron on Nitrogen atom.
N
p
hr + n
c
h C

hr + H
h
h
The atmospheric carbon dioxide
a mixture of
14
CO2 and
12
CO2 present in
a fixed ratio. Plants absorb CO
2 from the atmosphere and prepare cellulose
(wood) by photosynthesis. As long as the plant is alive the ratio of
14
C to
12
C
atoms in the wood is the same as in the atmosphere.
When the tree is cut, this cycle stops and the ratio
14
C to
12
C begins to
decrease because the
14
C atoms are constantly disintegrating. The concentration of
14
C can be measured by counting its radioactivity.
If N0 concentration of
14
C in fresh (living) tree
Nt concentration of
14
C at particular time t (after cutting),
The age of
the historical object (i.e. time, t), can be determined by formula,
λ =
etmcm
i
log
nc
ni
where, λ = 0.693 / g
hae
here, g
hae Half life period of radioactive carbon (
14
C). = 5730 years.

Preparation of transuranic element:-
When Uranium is bombarded with neutrons of certain velocity, one neutron is
captured and gives new isotopes of uranium.
U
ye
em1 + n
c
h U
ye
emy + γ H
h
h
This isotope of Uranium is much more radioactive than natural Uranium. It
emits a beta particle and gives Neptunium having atomic number 93 which is
does not occur in nature.
U
ye
emy Np
ym
emy + e
2h
c
Neptunium is also radioactive and emits a beta particle and gives Plutonium
having atomic number 94.
Np
ym
emy Pu
yr
emy + e
2h
c
Plutonium further undergoes beta-ray change and in this way, by
appropriate nuclear reaction new elements are formed. (Americium-95,
Curium-96, Berkelium-97.....etc)