Dr. Edward Murphy, University of Virginia, gave a profound talk on how stars create heavier elements from hydrogen and helium. One of the slides is remarkably informative, and supplements the periodic table:
– almost all elements come from inside stars
– at 100 million degrees, massive stars create elements up to the atomic number of iron (Fe)
– as the star goes supernova (or when binary stars collide), massive stars create the elements beyond iron (including precious metals) in about 2 seconds
– because the atomic numbers for helium (He) are even numbers, about 10x as many elements have even atomic numbers compared to odd numbers, presumably because the even elements result from common nuclear formulae
– some of the elements are much less common than expected, like Li and De, so presumably they are consumed in nuclear reactions, like helping fusion (confirmed as they’re both used in nuclear weapons production)
– iron is the most stable element, hence nuclear reactions result in iron, which then slows down later reactions since iron doesn’t participate in reactions until very high temperatures at the end of the star.
– life on earth is made mostly from carbon and oxygen due to their reactivity and abundance. This is likely on other planets.