Arsenic: My Element of the Week

Why Arsenic you ask? I dunno. It's got that whole romantic Victorian poison of choice thing going on. Arsenic and Lace. Always getting a bad rap by being the vehicle of murder most foul. And it sounds pretty. Arsenic . . . rolls off the tongue. So, what do we know?
As, having an atomic number of 33 and an atomic mass of 74.92160 . . . So that's 33 protons, 33 electrons and about 42-ish neutrons. Let's see if I can remember how to do this.

As = 1s22s22p63s23p63d104s24px14py14pz1
or
As = [Ar]3d104s24px14py14pz1

Okay, I think that's right.

So what else do we know about As? It's allotropic, which means that it can be the same molecules looking and maybe acting different depending on how those molecules are arranged. It can be yellow and soft, waxy, but only if the molecules are arranged as a tetrahedron. It can also be brittle and grey, metallic, when arranged another way, and much more dense. It's a little unstable and lends itself to converting and changing itself in many different ways. It is easily dissolved in water, and when dissolved becomes a powerful acid. It can be heated and turned into a gas, also easily. In addition to being used as a poison, it was also used as a stimulant and medicine. It resembles phosphorus, which is directly above As on the periodic table.

Over the years it has had a patchy reputation and has gone in and out of favor in it's different incarnations. Sometimes as a food additive, sometimes as a recreational drug or medicine. We all know of it as a poison, and it has been widely used as herbicides, pesticides, and insecticides. All in all, I can say that it seems to have many uses, and should be handled with respect and caution. After all, it is the Poison of Kings, and the King of Poisons.