Dalton's Atomic Theory
... of one element were always the same in size, shape and weight, and that these attributes were unique to that element. Atoms of another element would have different sizes, shapes and weights. For instance, the atoms of carbon will always be the same, no matter where in the world they are located and no other element can have atoms that are the exact same size, shape and weight as the atoms in carbon, or they would in fact, be carbon. His third idea was that during a chemical change, the atoms of the elements involved combine to form molecules of an entirely new material. He also said that molecules are the smallest parts of a compound that still have the compound's properties, such as texture, mass and phase. His last idea was that, during a chemical change, the atoms inv...