Particles Associated with Nuclear Reactions

There are a number of particles associated with nuclear reactions.

The first three are what we generally think of as the common types of radiation. These are also known as ionizing radiation because they have enough energy to knock electrons out of atoms (thus creating ions).

alpha particles -

alpha particles are identical to the nucleus of a helium atom (2 protons and 2 neutrons) and can also be shown as ⁴₂He (where the 4 is the mass number and the 2 is the atomic number, see the section on symbols if you aren't sure how that works.)

Alpha particles are heavy, and can cause damage when they hit a cell, or more specifically, when they hit the DNA of a cell, which can lead to cancer.

However, alpha particles can travel only a few centimeters through air and cannot penetrate skin, so something that emits alpha particles is not dangerous OUTSIDE of your body. Inside your body, they can be very dangerous.This can happen if you were to inhale dust particles that contained radioactive materials. This is also how Alexander Litvinenko was assassinated.

beta particles -

Beta particles are electrons that are emitted from the nucleus of an atom. Of course this is bizarre given that there are no electrons in the nucleus. Emission of a beta particle involves the transformation of a neutron into a proton and an electron. The proton stays in the nucleus and the electron is emitted.
Beta particles can be written ⁰_-1e (Here the -1 indicates that the charge is equivalent to the opposite of a proton charge -- not that there are -1 protons)

Because beta particles are so small and travel so fast they can travel much further through air than alpha particles can. In addition they can penetrate through clothing and skin. Beta particles can cause damage to cells that lead to cancer, but they can also cause burns and tissue damage and lead to other symptoms of radiation sickness.

Beta particles can be blocked by most solids.

gamma particles -

Gamma particles are high energy photons - pure energy, in fact gamma rays have more energy than x-rays, and therefore can travel through you. This means that they can damage any and all of you - from your exposed skin to the marrow inside your bones.

Gamma rays have so much energy that it takes several inches of lead (or feet of concrete) to shield you from gamma radiation.

The other particles on this list are much rarer, although they are also dangerous.

neutrons -

neutrons are the neutral particles normally found in the nucleus

positron -

positrons are identical to electrons except that they are positively charged instead of negative. These are the anti-matter version of electrons. The sub-scripted 1 here does NOT means that this contains a proton - only that the charge is equivalent to that of a proton

electron capture - E.C.

electron capture is the name applied when an electron is "captured" by its nucleus. This process involves the conversion of a proton (and the captured electron) into a neutron.