Atomic mass of Carbon 1201. This list contains the 118 elements of chemistry. 63 546 Represents The Atomic Mass Of The Element Copper Copper Heavy Metal Poisoning Copper Properties Although you can specify atomic mass in kilograms atomic mass is usually expressed in atomic mass units u also known as Daltons Da. . Its monatomic form H is the most abundant chemical substance in the Universe constituting. Development of atomic theory. The concept of the atom that Western scientists accepted in broad outline from the 1600s until about 1900 originated with Greek philosophers in the 5th century bceTheir speculation about a hard indivisible fundamental particle of nature was replaced slowly by a scientific theory supported by experiment and mathematical deduction. One such Unit is Equal to One-Twelfth of the Mass of a Carbon-12 Atom Which is at Rest. We can also use molecular weight calculator for finding molar mass of a. About T