One thing that’s always fascinated me is how you can take three basic particles(protons, neutrons, electrons) and get over 100 different elements. And some elements react to form compounds which create even more different things, an infinite number of things I imagine.
Here’s what I want to know though. Is there any way for the properties of a new element(such as one of the artificial ones high up on the periodic table) or a new compound to be predicted, or do they only find out once the new element or compound has been created?
For example, is there a way to predict on paper that two atoms of hydrogen and one atom of oxygen make water, but add another oxygen atom and I get peroxide?
That’s exactly what Mendeleev did when he started putting together the Periodic Table of the Elements. He arranged the known elements by their similar reaction properties (we now know that these properties are due to how electrons are arranged, but Mendeleev didn’t know about electrons.) When he was done, he noticed there were several gaps in the table. He predicted that elements would be discovered which would fit in those gaps, and what their properties should be. Sure enough, those elements were discovered, and their properties were very close to his predictions.
As for more complicated molecules, we can now use computer simulations to get reasonable predictions about what they will do under certain circumstances.
But ultimately you still have to break out the beakers and stuff to be sure. Our predictive models of this stuff are a lot better than Mendeleev’s were, but are still incomplete.
Since most pharmaceuticals are just compounds anyway, at some point won’t it be possible for a computer to just tell you, “hey, get these ingredients and cure diabetes!”?
Of course, part of the difficulty is that our standards have changed. Chemists of Mendeleev’s time would have been excited to successfully predict things about molecules with only a handful of atoms, like water, ammonia, or nitric acid (OK, it’s not actually a “prediction” when you already know all of water’s properties, but that’s the idea). Nowadays, our goals are considerably loftier: Chemists nowadays spend their time on trying to predict things about molecules with thousands of atoms, like proteins.
EDIT: We do do computer searches for potential drugs now, but even in the happy event that we do find one, it’s a lot more complicated than “get these ingredients”. The ingredients for almost any drug are going to be mostly carbon, hydrogen, and oxygen, with a bit of nitrogen, phosphorus, and sulfur, plus maybe a few other trace elements. The proportions will even be pretty close, for most of them. But the hard part is in how they’re arranged, and how to get them to be arranged that way.
It always amazes me that Mendeleev’s work basically found an “echo” of some deep truths about angular momentum in quantum mechanics, discovered without any knowledge of QM just from observations of chemistry.