Elements!. Elements. A pure element is made of many of the same atoms. Common elements- Aluminum, Oxygen, Carbon (about 100 others) Elements cannot normally be broken apart into smaller substances. Demitri Mendeleev- Russian chemist who developed the first periodic table in 1869.
Demitri Mendeleev- Russian chemist who developed the first periodic table in 1869.
The periodic table organizes elements by common characteristics!
(atomic mass unit)
Atoms are identified by their number of protons.