Element of the Month: Argon!

April's Element of the Month:

Argon!
Ar
18

Atomic Mass: 39.948 amu
Melting Point: -189.34 °C
Boiling Point: -185.848 °C

We are immersed in Argon, but never think about it. I mean, everybody knows that Oxygen is a highly desirable component of the Earth’s atmosphere, and most folks realize that it is, atmosphere-composition wise, the smaller, feistier, more dynamic partner of big, slow, deadpan Nitrogen. But after Oxygen and Nitrogen, there’s still one percent of the atmosphere to account for, and that one percent is Argon. And sure, Argon is definitely the very junior partner in the trio, but it's one percent of the stuff that you compulsively suck into your very lungs 25,000 times per day.  That's a big deal, n’est-ce pas?

So, if we are continuously drawing this stuff into the core of our bodies – and we are – what is it doing in there? The answer is kind of counterintuitive. Because with Oxygen, well, you’re basically made of Oxygen. And, Nitrogen makes up 3.2 percent of your body, and without it, I assure you, you won’t get far on foot. Whereas, Argon does nothing in your body. Absolutely nothing. You draw it in, and then you just cast it back out again. It just slides off of your biology like water off of a duck’s back, except moreso. (And before you even wave that 2013 article from Medical Gas Research claiming the contrary in my face, give it a close read. Claptrap shouldn’t have been given a passing grade, much less made it through peer review.)

The reason Argon is such a non-player in the human physique is that it’s one of the “noble gasses.” Like fellow noble gasses Helium and Xenon and so forth, it has a number of electrons that is “just right” according to the arcane rules of atomic-level matter, and this allows it to pretty much remain above the fray of chemical reactions. If you’re a molecule with a positive or negative charge that you’re looking to balance out, an atom of Xenon does not give one shit about your problem. Go talk to Chlorine.

It is, of course, colorless and odorless. This is an “of course” for the same reason that Oxygen and Nitrogen are “of course” odorless and colorless: your nose and eyes wouldn’t work if things were otherwise. Imagine, for instance, that Argon was a fetching deep green and smelled like warm cinnamon rolls. It would not be without its charms, but you wouldn't be able to see anything but the thick green fog surrounding you, and you wouldn’t even smell the open sewer as you blindly staggered toward it. Plus, you’d be hungry all of the time.

The Centerfold!
 

But if you’re thinking “golly, we sure are lucky that Argon is colorless and odorless,” you’re not thinking big-picture. Luck has nothing to do with it. The deal is, your visual and nasal equipment developed through the ruthless process of trial and error over inconceivable time scales that we call “evolution,” most of that time hosted within creatures that you would not immediately recognize as kin. The sensory innovations that enhanced survivability were the ones that worked in the atmosphere that encases us here on beautiful Earth. "Working," by definition, means not responding to the stuff that encases us, like Oxygen and Nitrogen and Argon.

However, imagine that you and a special friend were chosen as colonists on the first Earth colony in another solar system, and you settled in on a planet with a good Oxygen-Nitrogen balance but no Argon. Probably, you’d never notice that anything was missing. But then, imagine that your children took a special tour back to see all of the famous places from the Home World that you were always going on about. I have a strong suspicion that they’d think “huh, this planet smells a little different. It’s got that Earth smell.” And that would be the Argon, acting on an uncalibrated nose. I’m just theorizing here.

Now, there is one slightly dangerous thing about something that is odorless, colorless, and non-reactive. There are a few cases on record where people have found themselves in an Argon tank or within a major Argon spill. And what happened? Well, they didn’t really notice. They breathed in Argon, they breathed out Argon, it felt pretty much like air, and it didn’t hurt them a bit. The only problem was what they weren’t breathing, which is to say Oxygen. And in those circumstances the road from disorientation to unconsciousness to death is an awfully short one.  So be careful down at the Argon plant, OK?

All right.  Even if you knew all of the above, I bet you didn’t know that although most of the Argon in the universe is Argon-36, what we have here on Earth is mostly exotic Argon-40. The former is what gets pumped out by nucleosynthesis in the crazy cornucopia of Elements that stars generate when they die. Most of our hometown Argon, on the other hand, comes into being when a mildly radioactive isotope of Potassium kicks out a neutrino. This happens, interestingly, around 435 times a second within your body, although perhaps less if you have a small frame. For me, it’s probably more like 510 times a second. I’m a regular Argon factory!

I feel bad about not mentioning Henry Cavendish, a brainy Age of Enlightenment fellow who has received fairly short shrift in these pages. But, I feel I’ve probably already said enough about Argon, which he discovered.

Argon, by Cornish painter Sean Hewitt.