The zig-zag line in this diagram separates the metals, on the left, from the non-metals, on the right. Hydrogen is a non-metal but it is often put in the middle. Most elements are metals, rather than ...
Everything we can see and touch, and quite a lot that we can’t as well, is made of tiny particles called atoms. Some substances, like particles of this iron, contain only one kind of atom. Iron is an ...