Dalton proposed modern atomic theory. What are his four main points?

Created the atomic theory. In 1303, he inherited the simple atomic theory of ancient Greece and Newton's particle theory, and proposed the atomic theory. Its key points are: (1) Chemical elements are composed of indivisible particles - atoms, which are the smallest indivisible unit in all chemical changes. (2) The atomic properties and masses of the same element are the same, while the properties and masses of the atoms of different elements are different. Atomic mass is one of the basic characteristics of elements. (3) When different elements are combined, the atoms are combined in simple integer ratios. Derive and prove experimentally the law of doubling. If the mass of one element is fixed, then the mass of the other element in various compounds must be a simple integer ratio. He was the first to engage in the work of determining atomic weights, proposed the method of relative comparison to determine the atomic weights of various elements, and published the first atomic table, which opened up bright prospects for subsequent work on determining the atomic weights of elements. It is recommended to use simple symbols to represent the composition of elements and compounds. In addition, Dalton's contributions to meteorology and physics are also outstanding. He was a meteorological fan. He began to observe the weather continuously since 1787, and he kept observing the weather continuously until a few hours before his death. He wrote down a meteorological diary of about 200,000 words. In 1801, the law of partial pressure of gases was also proposed, that is, the total pressure of a mixed gas is equal to the sum of the partial pressures of the component gases. He also determined the relationship between the density and temperature changes of water and the equal thermal expansion coefficient of gases. Unfortunately, Dalton was known as a "joke" because he stubbornly opposed the Avogadroist doctrine that came to his rescue. Dalton read and published 116 papers throughout his life, and his main works include two volumes of "A New System of Chemical Philosophy". In order to devote his life to science, Dalton remained unmarried and engaged in scientific research under poor living conditions. The British government only provided pensions at the appeal of famous European scientists, but Dalton still used it Save money and donate it to the University of Manchester for student scholarships. Dalton's life was just as Engels pointed out: The new era of chemistry began with atomism, so Dalton should be the father of modern chemistry. Dalton wrote down the key points of atomic theory in his notes: (1) Atoms are very tiny, indivisible particles of matter that make up chemical elements. Atoms maintain their original properties during chemical reactions. (2) All atoms of the same element have exactly the same mass and other properties. Atoms of different elements have different masses and other properties. Atomic mass is the most fundamental characteristic of atoms of every element. (3) When atoms of elements with simple numerical ratios combine, chemical reactions occur between the atoms to form compounds. The atoms of a compound are called complex atoms.