Final answer:
Major scientific achievements in atomic theory include the discovery of electrons and the nucleus, development of the periodic table, and advancements in quantum mechanics. These discoveries have been essential in understanding atomic structure and properties, contributing to the modern atomic model and broader molecular theory.
Step-by-step explanation:
Major Scientific Achievements in the Understanding of the Atom
The major scientific achievements of scientists who contributed to our understanding of the atom include the discovery of the electron, nucleus, and atomic structure. This groundbreaking work laid the foundation for our modern model of the atom and provided a framework for understanding atomic interactions. The discovery of the electron by J.J. Thomson led to the Plum Pudding Model, which was later revised by Ernest Rutherford's discovery of the nucleus. Rutherford's work unveiled the existence of the proton and paved the way for the discovery of the neutron by James Chadwick.
Another significant contribution was the development of the periodic table, which organized elements by their atomic weights and properties, underpinning the systematic understanding of the elements. Additionally, Niels Bohr's theory contributed substantially to the arrangement of electrons around the nucleus in discrete energy levels, which was essential to the advancement of quantum mechanics. These achievements not only defined the atom's structure but also facilitated the development of atomic and molecular theory, explaining many properties such as friction, cohesion, and adhesion as manifestations of electromagnetic forces.