Over the ages, many ideas were formed about what all matter is made of. The ancient Greeks believed there to be only four elements- air, earth, fire, and water. We now know that elements are the simplest type of a pure substance. Because of the many different properties of elements, they have been organized in lots of different ways. Dmitri Mendeleev devised the periodic table that we use today. He lined up all of the …showed first 75 words of 735 total…

…showed last 75 words of 735 total…elements, but their properties could be totally different. You can determine how different chemical compounds will often react if you know of a similar previous reaction. 6. When an element is made in a particle accelerator by the collision of high-speed particles and exists for only a fraction of a second, it should be considered a new element. This is because it's still a new type of simplest substance, regardless of how long it's in existence.