Final answer:
The correct answer is the A. Periodic Table, where elements are organized based on their atomic number and chemical properties.
Step-by-step explanation:
Over 100 existing elements are listed and classified on the Periodic Table. The Periodic Table is a cornerstone of chemistry because it organizes all known elements based on their chemical properties. Elements are arranged in order of atomic number (the number of protons in the nucleus), and elements with similar chemical properties are grouped in columns. Additionally, most Periodic Tables provide essential information such as the element's symbol, the atomic mass, as well as specific details like chemical reactivity and physical state at room temperature. The Periodic Table, first devised by Russian chemist Dmitri Mendeleev in 1869, continues to be an invaluable tool for scientists in understanding and predicting how elements behave.
The correct answer is A) Periodic Table. Over 100 existing elements are listed and classified on the Periodic Table. It is a tool used in chemistry to organize all of the known elements based on their chemical properties. The elements are arranged in order of atomic number, with elements of similar properties grouped together in columns.