There are lots of different substances but only just over a hundred elements. An element is a substance that is made up of only one kind of atom. The atoms in a particular element are the same as each ...

Elements and Compounds: Understanding elements and compounds is basic knowledge to study chemistry. Elements are the basic building blocks of matter, while compounds are substances formed when two or ...

A pure substance made from more than one type of element chemically bonded together. Elements bond in fixed ratios and so can be represented by a chemical formula. For example, sodium chloride has the ...

Chemical Reactions: A chemical reaction is a process where the substances 8unbdergo a change in their chemical composition. The substances that enter the reaction are called reactants that are then ...