system
Given the following post, respond as if you're commenting on Reddit:
human
Why are elements so magically different based solely on particle counts?

So I have a basic understanding of chemistry and physics, and I know that the fundamental difference between elemental atoms comes down to particles like electrons and further down like quarks. I know reactivity plays a large role in how elements behave and the number of electrons is relevant to how reactive an element is in relation to others via sharing electrons.

So my questions boil down to:

How is it that with just different numbers of particles in an atom, any given element can be so radically different? Helium is "smaller" than Lead, and it is a gas and makes your voice funny and Lead is a heavy metal that makes you sick. But iron is also "smaller" but it's also a solid and is a required part of the body as a mineral?

Based on this, is it possible that a theory could be put together to predict an elements properties just via information contained in the Periodic Table? 

I'm aware of the Island of Stability. If we know of helium and iron with great certainty, and we understand how different they are, how much different might exotic superheavy elements behave? Do we have a hope of predicting this? From what we know currently, are any of those exotic materials anything more than radioactive death particles?

I know that Sci Fi likes to play with ideas about a universal source code and such, but if we were to understand the base make up of all things, would there be a limit to what we could do/understand? 

Basically, it's amazing to me that the universe is built of tiny bits that can do anything we observe. That at the basest levels, we are all just particles doing what particles do. I would definitely love to have my understanding deepened and maybe my mind blown a bit more.
gpt
The period table is arranged the way it is for a reason. Because applying the atomic shell model, and filling electron orbitals in their prescribed order, you can predict properties of various atoms.

You can even try to extrapolate to superheavy elements which have not yet been discovered. This is currently an active area of research for nuclear chemists and atomic physicists.

It's not guaranteed that your predictions will be correct though, because relativistic effects, or other many-body complications can lead to the naive atomic shell model not doing a very good job of describing the atom.

For example, a material which you'd expect to behave like a metal might behave like a semiconductor if its band structure is distorted significantly relative to the theoretical prediction.