# Why are the properties of elements/atoms so varied? [duplicate]

How come atoms can have such a wide range of appearance, as well as atomic & chemical properties?

At one point you have something invisible & gaseous at room temperature, add a few protons/neutrons/electrons, and you have something solid & shiny. Seems like a huge difference for a small change.

Even within the same element you can have a wide spectrum of properties - carbon for example has a few quite different allotropes (e.g. diamond vs graphite vs Q-carbon).

I'm not so much interested on how these differences arise (e.g. valence electrons), but rather why they are so varied. (Which is why I don't think this is a duplicate of either Do current models of particle physics explain the chemical properties of elements/compounds? or What enables protons to give new properties to an atom every time one is added?)

• What kind of answer do you expect to "why" so it is not covered by the answers to "how" in this case? – nasu May 29 '17 at 16:11
• I don't really know myself what kind of answer I'm expecting. I'm guessing less of a "technical" one, more along the lines of r/explainlikeimfive ... when I started thinking about this, I was intrigued how varied elements are, considering it's "just" a slightly different mix of particles in each. – Orangenhain May 29 '17 at 20:39

The most obvious issue is that the electronic configuration determines periodicity in chemical behavior. Further, each new proton also shrinks the mean orbital radius of the outermost electrons, while electrons entering a higher energy level expands said radius. Charge-to-size ratios (for atoms, never mind the more numerous kinds of molecule) thereby end up all over the place, with implications for density, electronegativity and melting and boiling point. All this results in characteristic behaviours of s- and p-block elements, becoming truer in later periods for left-hand groups and less true in later periods for right-hand ones, and molecules being nothing like their constituent atoms (as usually they have full outer electron shells). For example, later alkali metals (halogens) more (less) readily lose (gain) electrons because of smaller $Z/r^2$ values.