Balancing Nuclear Equations
Name: Period:
There are two types of nuclear reactions: Fission, where a nucleus breaks into two or more pieces, and
fusion where two or more nuclei combine to form a new element. In nuclear reactions, only the nucleus is
involved. Electrons are ignored. Some atomic nuclei are inherently unstable and spontaneously change or
“decay”. There are four types of decay:
Type
Symbol
Charge of
particle
Mass(AMU)
Effect on
Atomic #
Effect on Atomic
Mass
Strength
Alpha
α
+2 (He
nucleus)
4
decrease by 2
decrease by 4
Stopped by
paper
Beta-
e- emission
β-
electron
-1
0
increase by 1
0
Aluminum Foil
Beta+
e- capture
β+
Positron
+1
0
decrease by 1
0
Aluminum Foil
Gamma
γ
none
none
none
none
Lead
The net result of α, β- or β+ decay is a new element. In b- decay, a neutron decays into a p+ and an e-
which is then ejected. In β+ decay a p+ captures an e- and transforms into a neutron. But despite the nature
of the reaction the law of conservation of matter still applies and the equations are balanced the same way.
Note α particle is a helium nucleus!
Another type of reaction occurs when something impacts a nucleus. These reactions result either in
the nucleus splitting (fission) or the combination of two or more nuclei to form a third, different nucleus
(fusion).
Balancing Nuclear Equations: Matter must be conserved including all p+ & n˚. Example:
Decay reaction (α decay)
!
86
219Rn "2
4He+84
215Po
Fission Reaction
!
0
1n+92
235U"36
92Kr+56
141
Ba +30
1n
Fusion Reaction:
!
17
35Cl+1
1
H"18
36Ar
another example
!
1
2H+1
3H"2
4He +no
Practice
Fill in the missing symbol and name the reaction:
1.
!
1
3H"___________+#1
0e
2.
!
92
232U"90
228Th +___________
3.
!
58
144Ce"59
144 Pr+___________
4.
!
30
65Zn "___________++1
0e
5.
!
19
40K"18
40Ar +________
