Questions, answered simply

The periodic table is a chart of all 118 known chemical elements - the ingredients that make up everything in the universe. Elements are arranged by their atomic number (how many protons they have), and elements in the same column behave in similar ways.

There are 118 confirmed elements, from hydrogen (element 1, the lightest) to oganesson (element 118). About 90 occur naturally on Earth; the rest have been made by scientists in laboratories.

By default each colour is a family of elements - like alkali metals, noble gases or halogens. Elements in a family behave similarly. You can also colour the bubbles by state (solid, liquid or gas) or by electron block using the menus at the top.

Every element has a one- or two-letter shorthand, like H for hydrogen or Fe for iron. Some symbols come from Latin names - Fe is from "ferrum", Na (sodium) from "natrium", and Au (gold) from "aurum".

Yes - Periodic Bubbles is a free periodic table game. Pop element bubbles to collect all 118, race the three-level Pop Quiz, earn badges, and come back for the Daily Bubble - a Wordle-style daily element puzzle with a new mystery element every day.

The Daily Bubble is a daily periodic table puzzle, like Wordle but for chemistry. Guess the mystery element in six tries - after each guess the clues show whether the category, group, period, phase and atomic number are correct, too high or too low. Everyone gets the same element each day, so you can share your score grid with friends.

Yes - completely free, works on phones and tablets, and even works offline once you have visited. Pop bubbles, hear each element introduce itself, spin 3D atom models and test yourself with the Pop Quiz.

Press Tab until the bubbles have a yellow ring, use the arrow keys to move between them, type a letter to jump to an element by name, and press Enter to pop. The Pop Quiz works the same way.

Ten multiple-choice questions on symbols, groups, trends and electron structure, the same for everyone, changing every Monday. At the end you get a result code that a teacher can verify on the class results page, with no accounts involved.

Numerical data comes from the open Periodic-Table-JSON dataset, with two corrections noted on the About page. The written guides, element pages and articles are original to this site.

Yes. Everything in the teacher section is free for classroom use anywhere in the world without asking. The embed code on the teacher hub puts the bubbles inside Google Sites, Moodle or a school blog.