Final answer:
Robert Boyle defined an element as the smallest component of a substance that cannot be further chemically subdivided. This definition laid the foundation for the study of chemistry and the development of the periodic table by Dmitri Mendeleev.
Step-by-step explanation:
Robert Boyle defined an element in a manner that made it subject to laboratory testing. He is credited with rejecting the old Greek concept of earth, air, fire, and water elements and instead defining elements as the smallest components of a substance that cannot be further chemically subdivided. Boyle's definition of elements as indivisible units was a precursor to the modern concept of atoms. This definition laid the foundation for the study of chemistry and the development of the periodic table by Dmitri Mendeleev.