What was one idea dalton taught about atoms

The main points of Dalton's atomic theory, as it eventually developed, are: Elements are made of extremely small particles called atoms. Atoms of a given element are identical in size, mass and other properties; atoms of different elements differ in size, mass and other properties.

According to Dalton's atomic theory :

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.