# Periodic table of elements

the ultimate construction toy


Note that there are severe limits to the construction kit alalogy. But those can be easily avoided.

## Atoms as building blocks for engineering

The great things about atoms from an engineering prespective are:

• atoms do not wear ever (well disregarding exotic things like proton decay)
• atoms have no tolerances - they are completely indistinguishable (same isotope)
• interatomic bonds are compliant (low stiffness) - assemblies can be bent a lot
• interatomic bonds are strong (high force) - materials can be very strong

One could say that these properties of atoms makes the periodic table like the ultimate construction toy.

## The PToE as a construction kit - applicability and limitations to this interpretation

See main article: "Limits of construction kit analogy"

## Which elements are best to use

Metals on their own tend to form non-directed metallic bonds making it easy for thermal vibration to slide around metal atoms on metal surfaces. The atoms wander (diffuse) away. Even if one places the atoms with atomically precision in a sufficiently cooled state once the product warms up to everyday temperatures all the atomically precise structure gets scrambled up. Also most metals on their own are likely to oxidize when they come in contact with electronegative nonmetal elements making them swelling up (e.g. oxidizing / rusting)

In contrast nonmetals tend to form strong directed covalent bonds that do not diffuse at room temperature.

Out of this reason metals on their own aren't suitable for atomically precise nanosystems. Specifically life does not use metals on their own and even barely at all as building blocks. The main exception is Calcium in bones and teeth. But Natrium which is always free floating solvated and just serve electric signalling purposes is not counted here (Same with iron and other transition element metals). The preference of life for nonmetals can be seen by comparing the map of the nonmetals to the map of dietary elements. (TODO: add illustration)

In the context of semi advanced to fairly advanced artificial atomically precise nanosystems metals can be used if they are paired with electronegative nonmetals in very very roughly 1:1 .. 1:2 ratio. Then the bonds become more covalent in character and immobile. Many common gemstones fall in this category best known is sapphire the oxide of aluminum. Most of the gemstones we find in mountains are not synthesized by any lifeforms. Advanced atomically precise manufacturing makes accessible not only a super-set of both bio-minerals and mountain-gemstones but also gemstones completely out of nonmetals but in structures that life is not able to generate. The most prominent and commonly known example of such a gemstone out of dietary elements but that life is unable to synthesize is diamond (but there are more). Life is probably unable to generate those special gemstones because they can only be mechanosynthesized in practically perfect vacuum and there pretty much certainly exists no continuous evolutionary path toward the necessary advanced atomically precise systems that provide this practically perfect vacuum. It needs us humans to take this step and overcome this complexity barrier.

Other criteria for the choice of element to be used are:

• The abundance of the element in context of the place where it's going to be used or rather it's economic accessibility. See: Colonization of the solar system.
• The mechanical strength compounds including this element to a great percentage can have.
• The toxicity compounds containing this element usually have.
• Special physical properties that the element provides that cannot be emulated by metamaterials (e.g. the very high density of osmium)

## Philosophical observations

The periodic table of elements is probably out of good reason (minimal complexity?) not much bigger than it needs to be to allow the emergence of life in our universe. The minimalistic and general nature of our set of chemical elements allows us to use it like a construction toy in other more straight forward ways than life does.

## Related

[todo: add an image of the periodic table with highlighted elements of interest]