According to john dalton, elements consist of tiny particles called atoms of each element are to each other. consisted of atoms of different elements combined together.

According to john dalton, elements consist of tiny particles called atoms. Atoms of each element are similar to each other. Compounds consisted of atoms of different elements combined together.

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.