Radioactivity is the process in which particles in unstable atoms separate and fly off from the atom. The particles that come off from the atom are known as nuclear radiation, or radioactivity. This process as a whole is known as radioactive decay.
Radioactive materials under normal circumstances occur above the atomic number 83. All elements with a atomic number 84 or higher have all been proven to be radioactive. For example, Uranium is mildly radioactive, and its atomic number is 92. The atomic number means how many protons are in that atom and there are usually the same amount of electrons as there are protons. For example Carbon, has the atomic number 6. So there are 6 protons and 6 electrons in it, but it can sometimes have 0 or a ton of electrons in it. Remember: The number of protons are the only thing inside an atom that defines the element. But what about neutrons?
All elements above the atomic number 83 are radioactive however, the number of neutrons in an atom can actually make nonradioactive elements radioactive, and make radioactive elements even more radioactive. Here's how. There are usually a few more neutrons than there are protons in an element, but like electrons you can add as many or as little as you want. Electrons don't actually add any mass to the element but neutrons do. If you add 40 neutrons to potassium which only has 19 protons, it begins to become slightly radioactive. This is because the extra weight in mass begins to make the element unstable, thus making it radioactiv at can also make radioactive elements even more radioactive. For example take Uranium 235. The 235 stands for how many neutrons are in the atom. The amount of neutrons in an element is called an isotope. Anyway uranium 235 has so many neutrons that is incredibly radioactive and unstable. Its so unstable that it is the law in United States of America that you cannot have any Uranium 235 without a permit and a legitimate reason for needing it. This is because Uranium 235 is used for making nuclear bombs because it is so unstable.
Radioactive decay generates radioactive radiation when it occurs. But when it occurs the element actually changes into another. Radioactive decay gets rid of protons and neutrons and the number of protons defines the which element the atom is, so the element actually changes into another one. Example: Francium has a half life of 22 minutes, which means after a certain amount of time, half of a chunk of it will turn into another element then the remaining half of the francium there will take 22 minutes to decay. Then ¾ of the chunk will be astatine. Different radioactive elements have different half lives, some lasting a fraction of a second such as Ununpentium to some lasting billions and billions of years such as Bismuth, which is usually not considered radioactive at all.
Types of Radioactivity
There are 3 main types of radioactivity. Alpla beta and gamma radioactivity. Scientists still aren't sure what exactly causes these different types but they do different things. Most types of radioactivity can go though anything but lead but alpha radioactivity can be stopped with just a piece of paper. Beta radioactivity can go though most things except metal like aluminum or iron. But gamma radioactivity, the most common type, can go though anything except a thick sheet of Lead. Lead has enough mass to stop and deflect radioactivity. Lead is used heavily in nuclear power plants. And also used to make lead aprons that patients use in an X-Ray. X-Ray uses radioactivity pointed at a camera. Anything between the source and the camera in the beam appears see through in the camera. This is because the camera picks the radioactivity up as light and because it can go though things it makes it possible to see though what's there. You can see bones different though because it does slow down the radioactivity down the slightest bit. Lead is the only thing that can stop it though.
Heath Risks and Hazards
Radioactivity can be dangerous to humans and pretty much all living creatures. The radioactive particles or radiation can penetrate inside human cells, bringing nuclear energy where it is not needed, casuing a lot of damage. If it effects reproductive cells it can cause birth defects. Radioactive particles have been known to cause cancer to people who have been exposed to radio