Science
Periodic Table Deep Dive Quiz
Element 118, radioactive bananas, and the scientists who died discovering elements.
Element 118, radioactive bananas, and the scientists who died discovering elements.
Marie Curie's personal notebooks from the 1890s are so radioactive that they are stored in lead-lined boxes in Paris — and you must sign a waiver before handling them. This quiz goes deep on the periodic table: from the stories behind element discoveries to the weird physical properties that make chemistry endlessly surprising. Expect questions on dangerous experiments, record-breaking elements, and facts that sound impossible but are completely true.
Each round presents 10 randomized questions from a pool of 50, with four multiple-choice options and instant feedback after every answer. Your final score comes with a performance tier and shareable results.
You'll discover how Mendeleev predicted the existence of undiscovered elements before they were found, why francium is so rare there may be fewer than 30 grams on the entire planet at any given moment, and why gallium melts if you simply hold it in your hand. Explore the history of the Radium Girls, the first artificial element, the naming battles over nihonium and tennessine, and why the ocean contains enough dissolved gold to give every person on Earth a share — if only we could extract it cheaply enough.
Francium (element 87) is considered the rarest naturally occurring element on Earth. It is highly radioactive and decays so quickly that scientists estimate the total amount present in Earth's crust at any moment is less than about 30 grams. Francium exists only as a decay product of actinium and has a half-life of just 22 minutes for its most stable isotope.
Yes — bananas are mildly radioactive because they contain potassium-40, a naturally occurring radioactive isotope of potassium. The concept of a "banana equivalent dose" (BED) is used informally to describe tiny radiation exposures. Eating a banana exposes you to roughly 0.1 microsieverts of radiation, which is entirely harmless. Your own body is also naturally radioactive for the same reason: you contain about 140 grams of potassium, some fraction of which is potassium-40.
Russian chemist Dmitri Mendeleev is credited with creating the first widely recognized periodic table in 1869, arranging elements by atomic mass and noticing repeating patterns in their properties. What made his table especially remarkable was that he left deliberate gaps for elements he predicted had not yet been discovered — and those elements, including gallium and germanium, were later found with almost exactly the properties he had forecast. German chemist Lothar Meyer independently developed a similar table around the same time.
Last updated: March 2026