Untitled - Kelly Walsh High School

292 CHEMISTRY FOR THE UTTERLY CONFUSED
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Our goal in this chapter is to help you learn about nuclear reactions, including
nuclear decay as well as fission and fusion. If needed, review the section in
Chapter 2 on isotopes and the section in Chapter 13 on integrated rate laws
which discusses first-order kinetics. And just like the previous nineteen chapters,
be sure to Practice, Practice, Practice.
20-1 Nuclear Reactions
Most nuclear reactions involve the breaking apart of the nucleus into two or
more different elements or subatomic particles. If we know all but one of the
particles, then the unknown particle can be determined by balancing the
nuclear equation. When chemical equations are balanced, we add coefficients
to ensure that there are the same number of each type of atom on both the left
and right of the reaction arrow. However, in order to balance nuclear equations
we ensure that there is the same sum of both mass numbers and atomic numbers
on the left and right of the reaction arrow. Recall that we can represent a
specific isotope of an element by the following symbolization:
A is the mass number (sum of protons and neutrons), Z is the atomic number
(number of protons), and X is the element symbol (from the periodic table). In
balancing nuclear reactions, ensure that the sum of all A values on the left of
the reaction arrow equals the sum of all A values to the right of the arrow. The
same will be true of the sums of the atomic numbers, Z. Knowing that these
sums have to be equal allows you to predict the mass and atomic number of an
unknown particle, if we know all the others.
If we bombard chlorine-35 with a neutron, we create hydrogen-1 along with an
isotope of a different element. Write a balanced nuclear reaction for this process.
Solution:
First, we write a partial nuclear equation:
35
17Cl 1 0n A
ZX l 1 1H ?