Chemistry Reference
In-Depth Information
Symbols for Particles Common to Nuclear Equations
Alpha Particle—The alpha particle is identical in composition
(with 2 protons and 2 neutrons) to the nucleus of a helium atom.
It is also important to note that, like a bare helium nucleus, the
alpha particle is positively charged and will be attracted to a
negatively charged object.
4
2
He
Beta Particle—The beta particle is identical in composition (with
a mass of zero and a charge of -1) to an electron. Being negatively
charged, it is repelled by other negatively charged objects.
-1
0
Neutron—Sometimes neutrons are absorbed or released as
elements transform into other elements. Even more interesting is
the fact that protons appear to turn into neutrons (and vice versa)
in some nuclear reactions.
1
0
n
Positron—The positron (sometimes called a “beta plus particle”)
has the same mass as the electron, but has the opposite charge.
0
+1
e
Proton—The proton is identical in composition (with a mass of 1
and a nuclear charge of +1) to the nucleus of a hydrogen
(protium) atom. The nuclear charge of a proton is understood to
be positive, so the + sign is not always shown in the notation, as it
is with the positron.
1
1
p
Figure 6-5a
If you studied the concept of carbon dating in biology, then you know that
carbon-14 is an example of such an unstable isotope, which naturally de-
cays into nitrogen-14 according to the following nuclear equation:
14
6
C
14
7
N +
-1
e
This reaction is an example of beta decay, because the parent nucleus
decays into the daughter nucleus as it releases a beta particle.
Artificial radioactivity is observed when scientists take stable nuclei and
try to combine them in various ways in an attempt to produce stable isotopes
of “new,” or at least previously undiscovered, elements. All of the elements
on the periodic table with atomic numbers of 93 or greater were produced
with the aid of instruments called particle accelerators, which are used to
fuse nuclei of known elements together in order to produce still heavier
nuclei. All of these transuranium elements have proven to be radioactive,
and they decay into more stable elements after varying periods of time.
14
6
C
14
7
N
