Sunday, February 12, 2017

The peculiar thing about electrons

If you've taken a basic chemistry course you've probably been taught about electrons. In case you haven't, this is the gist of what you need to know.

Now every atom is made up of what is called a nucleus. In the nucleus you have two subatomic particles (not actually the smallest thing, they are made up of more fundamental molecules called quarks, but I won't get into them just yet), namely, protons and neutrons. There is one notable exception in hydrogen, which only has one proton in its nucleus, though its heavier derivatives, deuterium and titrium have one and two neutrons respectively. But I digress, protons are positively charged particles with a relative mass of 1, whilst neutrons and neutral (creative names I know); neutrons are also assigned a relative mass of 1 (atomic mass units). Now orbiting around this nucleus are electrons, which are negatively charged particles, with such as small mass as to be negligible. Now depending on where you are in your chemistry education you will have been taught different things about them.

"labeled for reuse" https://c1.staticflickr.com/9/8070/8207491443_4e0e42647b_b.jpg 

It's unlikely in this day and age that you've been taught the "plum pudding" model of the atom, as this was one of the earliest renditions, and other then getting the charges right, is pretty much wrong. What you were probably taught was the Bohr model of the atom. This states the electrons orbit the nucleus in concentric circles, like the planets the sun. There's really no eloquent way of putting this, but this is also wrong.

Just thinking of the behaviour of an electron, this is just a really unlikely circumstance. Electrons quite literally defy the laws of physics, and a new branch of it (quantum physics) had to be developed to explain these oddities (again I'll spare you the detail for now). Thus, knowing this what are the odds that electrons would be content orbiting a nucleus in quaint little circles? Quite unlikely.

Instead they are found in orbits. The shape and type of orbit depends on four different, unique, quantum numbers assigned to each electron, which I also won't get into. The nature of these orbitals can be determined using a very complicated equation derived by Schrodinger. The lowest energy orbital is essentially a sphere, followed by a larger sphere, which are then proceeded by more and more complicated shapes, some of which have yet to be derived. All I want you to know is that the area that the shape covers is said to be the area that particular electron occupies. But this shape is given by a probability density function, i.e. the resulting value is a probability. I can't quit recall the exact number, and it also depends on which orbital is being talked about, but suffice it to say it's less than 1. In other words, the probability of an electron being in that orbital is quite high, however, and here's where the crazy part comes in, if the electron is not in that orbital it can quite literally be anywhere else. It could, for example, be on the Great Wall of China, now the probability of this is very low, but it is not impossible.

Kind of neat to think some of your electrons might be whizzing around Antarctica right now.

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