Atomic theory

Atomic theory and ancient philosophy speculate that everything can be described by an infinite number of combinations of atomic particles (or atoms) of basic substances, all of which are hard and small and can not be divided in size. Chemical elements combined to form various materials consist of aggregates of similar subunits (atoms) that have the characteristics of the nucleus and electron substructures of each element. Ancient atomism was proposed by Greek philosophers Leucippus and Democritus in the 5th century BC and was revived by Roman philosopher and poet Lucretius in the 1st century BC. After the continuous improvement of modern atomic theory in the early 19th century, the work of British chemist John Dalton began to prosper. Experiments by British physicist Ernest Rutherford on the scattering of alpha particles in thin gold foils confirmed that the atomic Rutherford atomic model consists of positively charged cores with nearly all masses. Electron cloud of the planet surrounded by negatively charged ones

With the emergence of quantum mechanics and Schrodinger equation in the 1920's, atomic theory became accurate mathematical science. Austrian physicist Erwin Schchöderer designed partial differential equations for the quantum mechanics of atomic electrons, including the electrostatic repulsion for all negatively charged electrons and the attraction to the positively charged nuclei. This formula allows you to solve atoms containing only one electron (hydrogen) exactly, and you can find an approximation very close to atoms containing two or three electrons (氦 and lithium). To some extent, the Schrödinger equation can solve more complicated situations, and atomic theory can predict the nature of all atoms and their interactions from the first principle. Recently, high speed supercomputers can solve the Schrödinger equation, so you can accurately calculate the characteristics of atoms and molecules with more electron number. If a slight correction due to special relativity and the influence of quantum electrodynamics theory is also included, accurate consistency with the experiment can be obtained.

An important finding in atomistic chemistry is atomism, where John Dalton is associated with invisible atoms. Dalton's atomic theory is based on the belief that atoms are dignified by the difference in quality. He first described his theory at the Royal Society in 1803. The theory has six basic ideas: all substances are composed of atoms, atoms can not be made or destroyed, all atoms of the same element are the same, different elements are composed of various kinds of atoms . - In a chemistry laboratory for two weeks, I got a number 29 unknown liquid, and I had to find it through experiments I learned from the beginning of the semester. After conducting the experiment, we were able to find empirical formula, molecular weight, molecular formula, density, boiling point, and know what the substance is.

Atomic theory is a theory that explains the composition of matter. At atomism, we believe that substances can not be divided because they are composed of small particles called atoms that can not be separated. The word Atom is derived from Greek Atmos and has an inseparable meaning. Atom Theory Timeline - Year / Person Event 442 BCE Democritrus and Leucippus (Greek philosopher) proposed the idea that all problems consist of indivisible elements. - Instructional design learning theory is created by writing teachers and trainers of various education and training institutions, and training programs of various organizations. Relevant knowledge and skills are more effective, more attractive and effective for learners and are known as "educational design".