Meet the Elements

Look around. A leaf. A glass of water. A gold ring. The air you're breathing right now. Fire. They're all totally different stuff, right? So how many different KINDS of atoms does the universe actually have? A thousand? A million? Nope. One hundred and eighteen. That's the whole list. Everything you have ever seen is built from just those.

Back in eighteen sixty-nine, a Russian chemist named Dmitri Mendeleev started lining up the elements he knew about, sorting them by how they behaved. He noticed patterns. He drew a table. And here's the wild part — he LEFT BLANK SPOTS where he was sure new elements should fit, and even predicted what they'd be like. Years later, those exact elements were discovered, matching his predictions almost perfectly. That's the periodic table.

Here's how the table is wired. Each ROW — called a period — has elements with the same number of electron shells. Each COLUMN — called a group — has elements that BEHAVE alike. The far left? Crazy-reactive metals like sodium and potassium — drop them in water and they explode. The far right? Noble gases — helium, neon, argon — they don't react with anything. And the big chunky middle? Transition metals. Iron, copper, gold. The metals you've heard of.

Let's meet the stars. Hydrogen — lightest of all, the fuel that lights up every star. Helium — never reacts with anything. Carbon — the backbone of every living thing, including you. Nitrogen and oxygen — together, ninety-nine percent of the air you're breathing right now. Sodium — drop it in water and it literally explodes. And gold — pretty, rare, never tarnishes. There it is, the table's all-star team.

Your turn. Click any element up there to see its symbol, atomic number, what state it's in at room temperature, and where you actually run into it in the real world. When you're ready, switch to GUESS THE ELEMENT — I'll give you up to six hints, and you tell me which element I'm describing. Less hints, more points.

Some elements are just… weird. Mercury — a METAL, but liquid at room temperature. Gallium — solid in the box, but melt it in the palm of your hand. Sodium plus water? Boom. Fluorine is the most reactive element on the table — but tame enough, as fluoride, that it lives in your toothpaste. Uranium is the heaviest natural element, and it's slowly falling apart all by itself — that's radioactivity. The periodic table has a freak show.

So here's the whole picture. One hundred and eighteen elements. Organized by how they behave. Atoms in different combinations are the recipe for every single thing that exists — you, your phone, the air, the stars. From hydrogen at the top-left to oganesson at the bottom-right, that's it. The entire universe, in one table.