Choose an angle (such as materials, energy, research methods, environment, etc.). ) to talk about the development of chemistry (and have a mind map)

The development of chemistry in the 20th century Chemistry is a science based on experiments. Experiments and theories have always been interdependent and mutually promoting aspects in chemical research. After entering the 20th century, influenced by the development of other disciplines of natural science, the theories, techniques and methods of contemporary science have been widely used. Chemistry has made great progress in understanding the composition, structure, synthesis and testing of substances, and has made many important achievements in theory. On the basis of inorganic chemistry, analytical chemistry, organic chemistry and physical chemistry, a new branch of chemistry has emerged. The application of modern physical theory and technology, mathematical methods and computer technology in chemistry has greatly promoted the development of modern chemistry. /kloc-at the end of 0/9, the discovery of electrons, X-ray emission and radioactivity created conditions for the great progress of chemistry in the 20th century.

In structural chemistry, the modern nucleated atom model established by the discovery of electrons not only enriches and deepens the understanding of the periodic table of elements, but also develops the molecular theory. The application of quantum mechanics in the study of molecular structure leads to the emergence of quantum chemistry.

From the study of the molecular structure of hydrogen, the nature of chemical bonds was gradually revealed, and valence bond theory, molecular orbital theory and potential field theory were established successively. The theory of chemical reaction also goes deep into the microscopic field. Using X-ray emission as a new analytical method to study the structure of matter, we can deeply understand the crystal chemical structure of matter. There are three methods to determine the chemical three-dimensional structure: X-ray diffraction, electron diffraction and neutron diffraction. Among them, the application of X-ray diffraction method has accumulated the most accurate information of molecular three-dimensional structure.

Spectral methods for studying the structure of matter have also been extended from visible spectrum, ultraviolet spectrum and infrared spectrum to nuclear magnetic resonance spectrum, electron selective vibration spectrum, photoelectron spectrum, X-ray vibration spectrum and Mossbauer spectrum. Combined with computer, a large number of materials related to material structure and performance have been accumulated, which are developing from experience to theory. With the increasing magnification of electron microscope, people can directly observe the structure of molecules.

Due to the discovery of radioactivity, the classical theory of elements has undergone profound changes. From the establishment of radioactive decay theory, the discovery of isotopes to the realization of artificial nuclear reaction and nuclear fission, the discovery of deuterium, neutrons, positrons and other basic particles, not only human understanding goes deep into the subatomic level, but also the corresponding experimental methods and theories are established; It not only realized the ancient alchemists' idea of changing elements, but also changed people's world outlook.

As a symbol of the 20th century, mankind began to master and use nuclear energy. Radiochemistry and nuclear chemistry appeared one after another and developed rapidly. Interdisciplinary disciplines such as isotope geology and isotope cosmochemistry have been born one after another. The periodic table of elements has been extended to 109 element, and overweight elements are being explored to verify the "stable island hypothesis" of elements. The theory of element origin, which depends on modern cosmology, and nuclide dating, which is closely related to evolution, are constantly supplementing and updating the concept of elements.

In terms of chemical reaction theory, due to the improvement of understanding of molecular structure and chemical bonds, classical and statistical reaction theories have been further deepened. After the establishment of the transition state theory, it gradually developed into a micro-reaction theory, studied the micro-reaction mechanism with the molecular orbital theory, and gradually established the conservation law of molecular orbital symmetry and frontier orbital theory. With the application of molecular beam, laser and plasma technology, the detection and research of unstable chemical species has become a reality, so chemical kinetics has been possible to go deep into micro-reaction kinetics at the level of single molecule or atom from classical and statistical macro-kinetics.

With the development of computer technology, great progress has been made in quantum chemical calculation, chemical statistics, chemical pattern recognition, large-scale technical treatment and synthesis of molecules, electronic structure and chemical reactions, and some of them have gradually entered chemistry education. Regarding the research of catalysis, various models and theories have been put forward, from inorganic catalysis to organic catalysis and Munch catalysis, and the role of enzymes and the relationship between their structure and function have been studied from the perspective of molecular microstructure and size.

Analytical methods and means are the basic methods and means of chemical research. On the one hand, the classical composition and composition analysis methods are still improving, and the analytical sensitivity has developed from constant to micro, ultra-micro and trace; On the other hand, in the early stage of development, many new analytical methods can be used to analyze the structure, conformation, isotope, direct determination of various active intermediates such as free radicals, ionic groups, carbene, azabine and carbaryl, and to detect short-lived metastable molecules. Separation technology is also constantly innovating, such as ion exchange, membrane technology, chromatography and so on.

Synthesis of various substances is one of the purposes of chemical research. In inorganic synthesis, ammonia is synthesized first. The synthesis of ammonia not only initiated the inorganic synthesis industry, but also promoted catalytic chemistry and developed chemical thermodynamics and reaction kinetics. Later, coordination compounds such as ruby, artificial crystal, borohydride, diamond, semiconductor, superconducting material and ferrocene were synthesized one after another.

Under the impetus of modern industrial technologies such as electronic technology, nuclear industry and aerospace technology, the production technology of various ultra-pure substances, new compounds and materials with special needs has been greatly developed. The successful synthesis of rare gas compounds poses a new challenge to chemists, and it is necessary to re-study the chemical properties of zero-group elements. Inorganic chemistry is produced by mutual infiltration with organic chemistry, biochemistry, physical chemistry and other disciplines.

Metal chemistry, bio-inorganic chemistry, inorganic solid chemistry and other emerging disciplines.

The synthesis of phenolic resin opens up the field of polymer science. With the synthesis of polyamide fiber in 1930s, the concept of polymer has been widely recognized. Later, the synthesis, structure and properties research and application of polymers constantly cooperated and promoted each other, which made polymer chemistry develop rapidly.

The synthesis and application of various polymer materials provide various important materials with excellent performance and low cost for modern industry and agriculture, transportation, medical and health care, military technology and people's daily necessities, and become an important symbol of modern material civilization. Polymer industry has developed into an important pillar of chemical industry.

The 20th century is the golden age of organic synthesis. Great progress has been made in chemical separation methods and structural analysis methods. The structural problems of many natural organic compounds have been satisfactorily solved, and many new important organic reactions and specific organic reagents have been discovered. On this basis, fine organic synthesis, especially asymmetric synthesis, has made great progress.

On the one hand, various organic compounds with special structures and properties were synthesized. On the other hand, the basic substances of life, from unstable free radicals to bioactive protein and nucleic acids, were synthesized. Organic chemists have also synthesized natural organic compounds with complex structures and drugs with special effects. These achievements have greatly promoted the development of science; It provides favorable conditions for the synthesis of substances with high biological activity and the cooperation with other disciplines to solve the synthesis problems of biological substances and the chemical problems of prebiotics.

Since the 20th century, the development trend of chemistry can be summarized as: from macro to micro, from qualitative to quantitative, from stable to metastable, from experience to theory, and then used to guide design and innovative research. On the one hand, provide as many new substances and materials as possible for the production and technical departments; On the other hand, in the process of mutual infiltration with other natural sciences, new disciplines are constantly emerging and developing in the direction of exploring life sciences and the origin of the universe.

Classification of chemical disciplines

In the development of chemistry, according to the different types of molecules studied, the research methods, purposes and tasks are different, and many branches of different levels are derived. Before the 1920s, chemistry was traditionally divided into four branches: inorganic chemistry, organic chemistry, physical chemistry and analytical chemistry. Since the 1920s, due to the rapid development of the world economy, the birth of electronic theory and quantum mechanics of chemical bonds, and the rise of electronic technology and computer technology, chemical research has gained new means in theory and experimental technology, which has led to the rapid development and brand-new appearance of this discipline since the 1930s. At present, chemical content is generally divided into five categories, including biochemistry, organic chemistry, polymer chemistry, applied chemistry and chemical engineering, physical chemistry and inorganic chemistry, and actually includes seven branches.

According to the development of chemistry today and its mutual penetration with astronomy, physics, mathematics, biology, medicine, earth science and other disciplines, chemistry can be classified as follows:

Inorganic chemistry: elemental chemistry, inorganic synthetic chemistry, inorganic solid chemistry, coordination chemistry, bioinorganic chemistry, organometallic chemistry, etc.

Organic chemistry: natural organic chemistry, general organic chemistry, organic synthetic chemistry, metal and nonmetal organic chemistry, material organic chemistry and biochemistry.

Organic chemistry, organic analytical chemistry.

Physical chemistry: chemical thermodynamics, structural chemistry, chemical kinetics and physical chemistry.

Analytical chemistry: chemical analysis, instrument and new technology analysis.

Polymer chemistry: natural polymer chemistry, polymer synthetic chemistry, polymer physical chemistry, polymer application, polymer material resources.

Nuclear chemistry nuclear radiochemistry: radioactive element chemistry, radioactive analytical chemistry, radiochemistry, isotope chemistry, nuclear chemistry.

Biochemistry: general biochemistry, enzyme, microbial chemistry, phytochemistry, immunochemistry, fermentation and bioengineering, food chemistry, etc.

Other frontier disciplines related to chemistry include geochemistry, marine chemistry, atmospheric chemistry, environmental chemistry, cosmic chemistry, interstellar chemistry and so on.