What is an element?
Our understanding of what an element is has evolved over the years, but it’s still a tricky concept to nail down. Philip Ball investigates
As chemical concepts go, you don’t get much more fundamental than the element. It’s one of the first ideas that the chemistry student encounters, often in the iconic tabulation of these basic ingredients of nature that Dmitri Mendeleev first described 150 years ago and which is being celebrated this year. And yet no one can quite say what an element is. The question was debated with much vigour and occasional passion during a meeting of the International Society for the Philosophy of Chemistry in Bristol in July 2018 – but still without any consensus.
That’s no surprise. Some of chemistry’s finest minds, including Antoine Lavoisier, Mendeleev himself, and pioneer of nuclear chemistry Frederick Soddy, have grappled with it, yet still a concise and comprehensive definition remains elusive. And some of the participants of the meeting implied that might be for the best.