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 ...

Note: This video is designed to help the teacher better understand the lesson and is NOT intended to be shown to students. It includes observations and conclusions that students are meant to make on ...