Elements 114 and 116 are now the heaviest elements that we know for a fact exist. They can only exist for less than a second, but they get us ever closer to the fabled island of stability.
Researchers have been trying to produce definitive evidence for these elements for years, with the first announced discovery of element 114 happening back in 1999. A series of experiments in 2004 and 2006, jointly undertaken by teams in Russia and the United States, provided stronger evidence for these elements' existence, but it's only now that the Joint Working Party on Discovery of Elements has completed a three-year review and decided that those experiments do in fact represent definitive proof.
In order to create element 116, the teams smashed together curium atoms, which have 96 protons in their nuclei, with calcium nuclei, which have 20 protons. This created element 116 nuclei, which lasted for a few milliseconds before decaying into element 114 nuclei, which then in turn decayed into copernicium (element 112) after about half a second. They also managed to make element 114 directly by shooting calcium nuclei at plutonium atoms, which have 94 protons.
Getting official approval isn't easy - the same committee also looked at evidence for elements 113, 115, and 118, but these were all rejected. Elements 114 and 116 supplant copernicium as the new heaviest elements. In general, the discoverers get to pick the names, and the Russian team has said they will put forward flerovium for element 114 after the Soviet physicist Georgy Flyovov, while element 116 will be called moscovium after Moscow Oblast.
While we can say that these elements definitely exist, that's about all we can really say about them - unless we can find a way to make these elements stick around for a minute or more, we can't learn much about their properties. But chemists believe we're getting closer to the island of stability, a group of super-heavy elements that are stable enough to last for decades or more. The current thinking is that the island is centered around either element 120 or element 126, which means we could be getting very close to a bold new era in our study of the elements.
Pure and Applied Chemistry via New Scientist. Image of JINR synchrophasotron via.