elements

Elements are pure substances that cannot be broken down into anything simpler — they are the basic building blocks that every other kind of matter is made from.

• Every element is made of just one type of atom, identical to every other atom of that element and different from the atoms of any other element.
• Splitting water with electricity reveals two elements hiding inside it: hydrogen and oxygen — proof that they were never "made" of anything simpler to begin with.
• Elements fall into three families: metals (like iron and gold), non-metals (like carbon and oxygen), and metalloids, which sit in between the two.
• Of the 118 known elements, most are solids at room temperature, only a handful are gases, and just two — mercury and bromine — are liquids, which shows how differently elements can behave even though they're all equally fundamental.