How did they figure the atomic numbers?
The atomic age is a gift from the science of physics. It grew gradually through centuries as men probed into the nature of matter. In the past 100 years, many scientists from different nations added scraps of knowledge about the atoms from which all substances are made. We now have an orderly picture of these atomic elements. The periodic table of elcments gives the basic data on more than 100 different atoms. In the 1800s, scientists knew of only 50 of these elements. They sorted them into classes, such as metals and non metals, and compared their weights. In 1869, dimitri mendcleey arranged the known elements in a chart of rows and columns which made him known as the great grandfather of our periodic table. Mendeleev placed elements that were similar in chemical nature in the same column. The hard, glossy elements, copper, silver and gold, were listed one below the other, each heavier than the one above it. An orderly picture emerged with each element having its own atomic weight. Mo
