How can matter be classified based on how the atoms are arranged?

Matter can exist in three different states, solid, liquid, and gas, based on the way the atoms and molecules are arranged inside them. These three states are known as three different states of matter. In solids, atoms or molecules are tightly bound to one another thereby creating a rigid nature.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.