In most of these cases, light nuclei have had to smash together with enough energy to allow the strong force - a glue-like bond that forms when protons and neutrons get close enough to touch - to overcome the electromagnetic force — which pushes protons apart. If the strong force wins out, the colliding nuclei bind together, or fuse, to form a heavier nucleus.
Our sun is a good example of this. One of its main sources of power is a series of fusion reactions and beta decay processes that transform hydrogen into helium. Since the early s, when the existence of isotopes was first realised, nuclear physicists and chemists have been seeking out ways to study how isotopes can be formed, how they decay, and how we might use them.
As it turns out, the nature of isotopes — their chemical uniformity, their nuclear distinctiveness — makes them useful for a wide range of applications in fields as diverse as medicine, archaeology, agriculture, power generation and mining.
If you have ever had a PET scan , you have benefited from a byproduct of the radioactive decay of certain isotopes often called medical isotopes. We produce these medical isotopes using our knowledge of how nuclear reactions proceed, with the help of nuclear reactors or accelerators called cyclotrons.
But we have also found ways to make use of naturally occurring radioactive isotopes. Carbon dating , for example, makes use of the long-lived isotope carbon to determine how old objects are. Under normal circumstances, carbon is produced in our atmosphere via cosmic ray reactions with nitrogen It has a half-life of roughly 5, years, which means that half of a quantity of carbon will have decayed away in that time period. Gallium, atomic mass If the natural abundance of each isotope is Atoms are small, and it is possible to place 1.
Now, I state with absolute certainty that I have placed the same number of atoms on each balance! How do I know? However, the atom remains the same element whether it has a positive, negative, or neutral charge. The small, dense nucleus or center of the atom contains the other components—the protons and neutrons. Protons are positively charged particles, and the number of protons is always fixed for a particular element.
In other words, the number of protons is what gives each element its unique, individual identity. For example, a carbon atom has six protons, but an atom with only five protons is boron while an atom with seven protons is the element nitrogen. Neutrons are neutral - they have no charge. On the basis of this amount, the age of the material can be accurately calculated, as long as the material is believed to be less than 50, years old. This technique is called radiocarbon dating, or carbon dating for short.
Other elements have isotopes with different half lives. For example, 40 K potassium has a half-life of 1. Scientists often use these other radioactive elements to date objects that are older than 50, years the limit of carbon dating. Through the use of radiometric dating, scientists can study the age of fossils or other remains of extinct organisms.
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