I have a basic understanding of it. But mostly just from what I learned in high school. Also some from watching Periodic Videos on YouTube. Eli5: But why are there radioactive and other dangerous elements?
In: Chemistry
In the beginning, there was nothing. Then, that nothing decided to explode, and thus there became many things. Now, don’t ask why that happened, cos we’re still trying to work it out. That explosion was a whole fuck ton of energy. Some of this energy decided that it wanted to become matter instead. And it can do that, because matter is really just a reorganised version of energy. The energy became a bunch of subatomic particles, which eventually became a whole ton of hydrogen atoms.
These hydrogen atoms were so numerous that they began to group together. By grouping together, it created a large mass in one place, which warped the fabric of space-time, exerting a strong gravitational force and drawing in more hydrogen atoms. The more hydrogen atoms that came, the bigger the party got, making it easier for more hydrogen atoms to be drawn in. Now, when a bunch of molecules decide to have a party, it generates quite a lot of temperature and quite a lot of pressure. Eventually so many hydrogen atoms were joining in that the ones at the center were under a huge amount of temperature and pressure – enough that they spontaneously fused together to make helium. This generated even more heat, which caused even more fusion reactions and so on, until the entire ball of hydrogen became a huge fusion reactor – a star.
And there wasn’t just one star, there were many stars. Stars keep burning until all the hydrogen is gone, and there’s no more to fuse together. When that happens, the star explodes, becoming a supernova. When a supernova happens, the helium and any remaining hydrogen fuse together in random combinations, creating all the other elements. Elements like oxygen, and iron, and carbon, and a bunch of degenerate unstable atoms that chose to split up and become two separate particles instead.
These supernova then scattered throughout the universe, until they met more hydrogen, becoming great clouds of space dust called nebula. And out of these nebulae, new stars were born from the corpses of old stars. This time, the gravity of these stars caused them to create accretion disks of stardust – heavier elements that are drawn in by the star and orbit it at great speeds – similar to the rings of Saturn. Over time, these accretion disks clumped together under their own gravity, first forming rocks, then asteroids and finally planets. That’s right, you and everything else on earth are made of the dust-like remnants of long-dead stars.
But how does fusion work, you ask? Well, as you probably know, an element is defined by three subatomic particles: Protons, neutrons and electrons. These particles are under the effects of attractive forces, which feel quite similar to magnetic forces: protons stick to neutrons and electrons orbit around the big clump of protons and neutrons. Some arrangements of protons and neutrons are strong and stable. Every element on the periodic table is reasonably stable, and can exist in nature. Radioactive elements are elements that are not very stable – the repulsive forces of the protons is stronger than the attractive forces that hold the nucleus of the atom together. Very unstable elements split into smaller more stable elements almost immediately, but some radioactive elements are only a *little* bit unstable. These can exist for ages. The radioactive elements we consider true elements are unstable, but they’re not *very* unstable – they hold themselves together reasonably well, and decay spontaneously only quite slowly. However, you can cause them to decay earlier if you bombard them with energy, and this is how nuclear bombs work.
As for “dangerous elements” – there’s no such thing as a dangerous element. Life is just a very fragile thing, and some chemicals can break the mechanisms of life: Radioactive decay causes DNA to mutate, and arsenic sticks to important proteins and prevents them doing their job. The fact these things happen is kind of just coincidence. Hypothetically speaking, it would be entirely possible for life to evolve in a direction where arsenic *wasn’t* poisonous, but say, iron was.
All elements are made up of what are called protons and electrons. Electrons love protons and they will try and get as close to electrons as they can. You’d might think that this would lead them to flying straight to any near by proton, but that doesn’t happen. You see, Electrons really hate other electrons. Like really really hate. They will stay as far away as possible. So they want to go towards protons, but they can’t because other electrons are also trying to. Instead they maintain a distance from the proton, so that they can still be close to the proton, but far away from other electrons.
Because of all that the more protons you get in one place, the more electrons they will attract. Now imagine one proton and one electron. Obviously if an electron comes from the other direction it can get close to that proton without getting close to the electron. Because of this electrons will naturally fill up the space they can find around an electron. The farther away from the proton they are the more electrons they can fit at that distance.
Because of this the amount of additional electrons the atom can take, and the shapes they from change a lot as more protons collect in one place. Because of this different amounts of protons will have very different properties. So we call those different number of protons elements. If you look at a periodic table the atomic number of the element is it’s number of protons.
Think of matter like a puzzle, where each piece can connect to other nearby pieces only in certain ways. Tab A fits into Slot B, and so forth.
Sometimes, the puzzle pieces fit together very tightly. Sometimes they don’t, and when they don’t, they can fly off and hit other pieces to connect to. Some of those connections result in Very Bad Things.
For instance, you really need Tab A to fit into Slot B, but then Tab C shows up and it fits into Slot B instead. Tab A is pissed off, but it connects to something else. But back over in Slot B, the fact that Tab C connected now creates an opening for Tab X to connect and BLAM you have cancer.
Hi 🙂
The theory is that after the big bang, when everything cooled down enough, simple atoms formed from the “building blocks”, but only a lot of Hydrogen (in it’s most basic variant, you need just one proton), some Lithium.
Everything else was produced later.
Large clouds of hydrogen “clumped” together through their own gravity, to a point where these clouds got so dense and hot a fusion-process started: The first suns appeared.
Big ones. Didn’t last long.
Under extreme pressure, heat, fusion, it forms new elements.
The sun dies, a super nova occurs, and throws out a lot of stuff out into the universe again.
The elements clump together elsewhere, new suns form, again making all sort of new atoms. Helium, Carbon, Oxygen,Silicium… But once you get up to iron, that’s basically it.
Then, extreme events like super novae, blasting out matter, colliding with other matter, can make more complex atoms.
Some are not stable. They break into simpler atoms after a while, and that process can shoot out particles, radiation.
Essentially elements are a name that people came up with to distinguish one atom with one number of protons to a different atom with a different number of protons.
These elements behave differently mostly because of the way electrons arrange themselves when there are a different number of electrons, and the number of electrons is often the same as the number of protons.
Usually there are radioactive elements, because the number of protons and the number of neutrons determine how stable the nucleus of an atom are, and if a nucleus has a combination of neutrons and protons that is unstable, and there isn’t enough binding energy to hold the nucleus together, it can decay trying to find a more stable nuclei.
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