I have never been a fan of isotopes. I remember not understanding or knowing what an isotope is.

First, to fully know what an isotope is, you must know how an atom is structured.

1) i. Remember that the atomic number (the whole number) is the number of protons.

ii. Protons have a positive charge

iii. Protons make up the type of element – An element with 4 protons will always be Beryllium, an element with 12 protons will be Magnesium.

2) Remember that the atomic mass (the decimal number) is the total of protons added to neutrons.

ii. Neutrons have no charge

iii. Neutrons and protons are both found in the nucleus of the atom.

3) Isotopes are when elements have different amount of neutrons but still having the same number of protons.

In other words, elements such as carbon can have 15 known isotopes,  but only C-12 (regular), C-13 and C-14 are naturally occurring and C-14 is only found in traces. All these isotopes are still carbon but they all have different neutrons. C-14, commonly known as Carbon-14 is greatly used in archeology in dating samples.

Carbon-14 Dating

First of all Carbon-14 is a radiocarbon meaning that it will undergo radioactive decay by emitting beta particles.  As beta particles are emitted, the carbon-14 atom will eventually get smaller in this case will reach the half-life of its original state. Half-life is the time for the amount of carbon-14 to reach half of its amount, which is 5730 years!  Therefore, if someone can analyze the amount of carbon-14 available or left in a sample, they can trace back the amount of time that carbon-14 has disintegrated, thus, the time of origin of the sample.