(It's kinda long but makes you think)
In nearly every sci-fi or fantasy show you hear of fantastical new elements with amazing properties like latinum, dilithium and the ever lovable unobtainium.
An element by definition is a pure chemical substance that is made up of only one type of atom i.g copper, gold, oxygen etc.
Our little corner of the universe seems to be fairly representative of the bulk of the universe itself. Our sun appears to be made up of the same stuff all the other stars are, and Earth is likewise made up of similar elements that other rocky planets are.
So when we look for elements on Earth we expect to find them elsewhere in the universe, and we do.
Elements are placed into 3 categories:
1. Naturally occurring - hydrogen, iron, etc
2. Quasi-synthetic elements - elements that can exist in nature and are made naturally but that only last for brief periods or are found in only trace quantities. There are 6 of these elements known. Examples are plutonium and technetium.
3. Fully synthetic elements - is a chemical element that is too unstable to occur naturally on Earth, and therefore has to be created artificially. There are 24 elements that have only been discovered via their creation in a lab and can only exist in a lab.
There are 118 elements known, 1-94 occur to some extent naturally but elements 95 and higher are all fully synthetic.
Now, there are some pretty big rules and forces of nature that it seems gives us a maximum limit for the mass of an element before it spontaneously decays. Elements 101 and up have so much energy in them that their half-lives(t1/2) are all under 6 hours and many of them have t1/2 under 1 second.
In order for most elements to be useful they must have a stable isotope that lasts for at least a few hours. The problem of t1/2 and extreme radioactivity related to the mass of a new element can give us a prediction as to the maximum number of elements possible.
This "island of stability" can help us predict which transuranium elements might have a stable isotope and thus might either exist in some extreme star or be able to be created in a lab. It appears the maximum number of elements possible is between 124-130, all of those over 101 of course are incredibly radioactive and all over 110 don't last more than 10 seconds. Basically they blow themselves apart.
Another problem related to an element's usefulness is cost. A gram of weapons-grade plutonium (94) costs $4,000, however a gram of californium (98) would cost over $1 million to produce. (btw only 0.3g of californium are sold a year).
While the number of electrons for a given element may vary (U232, U238 etc) the number of protons (its atomic number) is pretty much fixed. For example there can't be an element 3.5 (3 being lithium and 4 beryllium).
So the question then becomes, is it realistically possible to find a stable, useful element that we don't know about that could have great properties like the fictional ones do?
Or, are we left to a universe with only 118-130 elements, of which 94 are fairly useful and cheap, but, perhaps could we find new combinations of the various elements and their isotopes that can give us awesome new chemical abilities?
Or finally, are we pretty much stuck with what we've got and mostly maxed out the number of useful elements and basic compounds? (basic being no more than 2-3 different elements combined together)
