I’ve been searching and can’t quite find the explanation I’m looking for. I’ve read that radioactivity comes from an atom containing too many neutrons, and so the neutrons will end up breaking off of the atom and go flying in some direction until it collides with something. Which leads me to my first part:
* What happens when this neutron collides with something?
* If we’re talking a person, I’m assuming it damages/destroys the cell it hits, does it bounce and keep destroying more? What if a person was exposed to insanely high radiation of this sort. Do they melt into a pile of goop as their cells are broken down?
I’ve read that the number after an element is supposed to represent the amount of neutrons. So Uranium-238 would have more neutrons than Uranium-235. But isn’t the protons/neutron/electron the entire makeup of the atom?
* How can the amount of neutrons differ and they still be considered the same element?
From what I understand, radioactive decay is what happens to a radioactive element naturally as it’s neutrons fire off.
* What happens to the element? Does it just eventually disappear or “evaporate”? What exactly happens to these atoms once the neutrons have all fired off?
* If the radioactive substance is a metal such as iridium, does it become super brittle once fully decayed? Crumble into dust?
I have absolutely no education or experience in this field, but it fascinates the hell out of me.
In: Chemistry
Just to clarify one part of this:
> How can the amount of neutrons differ and they still be considered the same element?
Chemical elements — what we mean when we say “elements” — are defined by the number of _protons_ they have. So uranium always has 92 protons, and hydrogen always has 1, and helium always has 2, and so on. The reason we use the number of protons for this is because the number of protons determines how the atom will deal with _electrons_, and that determines how the atom’s chemistry will work. So any atom with the same number of protons will behave chemically the same way as any other atom with the same number of protons, _no matter how many neutrons they have_. So helium is always helium, uranium is always uranium, and so on, as long as their proton counts stay the same. The periodic table of elements is a list of elements that orders them by their chemical affinities — a chemist can glance at it and say, “oh, this element would behave cheicallylike this other element other th
But as you note atoms can have different numbers of neutrons. Each type of element with different neutron counts is called an _isotope_. So Uranium-235 has 143 neutrons (92 protons + 143 neutrons = 235 nucleons). Uranium-238 has 146 neutrons (92+146 = 238). They behave _chemically_ identically, because they are both uranium (92 protons). But they behave different _physically_ because they have different neutron counts. So they have different radioactive half-lives, have different nuclear properties (U-235 is fissile, U-238 is not), and weigh different amounts (which is how they separate the two when they want to make U-235; because you can’t do it chemically, you have to rely on that tiny difference in mass).
When atoms undergo radioactive decay, their proton and neutron counts change, and so they become different elements. So Uranium-238 can lose an alpha particle (a helium nucleus, 2+2), and so it goes from 92+146 to 90+144, and thus becomes Thorium-144, a totally different element and isotope with different chemical and nuclear properties. Thorium-144 can also decay, and its decay product can decay, and so on, until you finally end up, after quite a long time, with Lead-206 (82+124), which is stable and won’t decay anymore.
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