Elements and Compounds. Section 3.4. Elements. An element is a pure substance that cannot be separated into simpler substances by physical or chemical means. Chemical names come from latin or other languages Chemical symbols are one two or (rarely)three letters long
Argon and potassium should be reversed if arranged by atomic mass. Mendeleev correctly arranged them thinking mass was wrong.
Table 3-5 Sucrose analysis from sugar cane
Mass ratio compound 1
Mass ratio compound 2