Hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, neon. Sodium magnesium aluminum silicon phosphorus, sulfur chlorine argon potassium calcium. Scandium, titanium, vanadium, chromium and manganese, iron, cobalt, nickel, copper and zinc. Gallium, germanium, arsenic, selenium, bromine, krypton, rubidium, strontium, yttrium and zirconium. Niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin. Antimony, tellurium, iodine, xenon, cesium, barium, lanthanum, cerium and neodymium. Samarium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium and ytterbium. Lutetium hafnium tantalum tungsten rhenium osmium iridium platinum mercury. Thallium, lead, bismuth, plutonium, plutonium, radon, radium, actinium and thorium. Praseodymium, uranium, neptunium, plutonium and americium.

periodic table of elements

In the periodic table, the elements are arranged according to their atomic numbers, with the smallest one in the first place. One row in the table is called period and one column is called family. The atomic radius decreases from left to right and increases from top to bottom.

In chemistry textbooks and dictionaries, there is a "periodic table of elements". This table reveals the secrets of the material world, unifying some seemingly unrelated elements to form a complete natural system.

Its invention is a pioneering work in the history of modern chemistry, which has greatly promoted the development of chemistry. When people see this watch, they will think of its earliest inventor, Mendeleev. 1869, Russian chemist Mendeleev arranged elements with similar chemical properties in the same column according to the relative atomic mass from small to large, and compiled the first periodic table of elements.

The periodic table of elements reveals the internal relations between chemical elements, making it a complete system and one of the important milestones in the history of chemical development.

With the development of science, the vacancies left by unknown elements in the periodic table have been filled one after another. When the mystery of atomic structure was discovered, the arrangement basis changed from relative atomic weight to proton number (extranuclear electron number or nuclear charge number) of atoms, forming the current periodic table of elements.

Number the elements according to their order in the periodic table to get the atomic number. The atomic number has the following relationship with the atomic structure of an element: number of protons = atomic number = number of electrons outside the nucleus = number of nuclear charges.

Using the periodic table of elements, Mendeleev successfully predicted the characteristics of elements (gallium, scandium and germanium) that had not been discovered at that time. 19 13 British scientist Moser used cathode rays to hit metals to generate X-rays. He found that the greater the atomic number, the higher the frequency of X-rays, so he thought that the positive charge of the nucleus determined the chemical properties of elements.

Elements are arranged according to the positive charge (i.e. proton number or atomic number) in the nucleus. Later, it was revised by many scientists for many years before the contemporary periodic table was formed. Elements are arranged in order of relative atomic mass from small to large, and elements with similar chemical properties are placed in one column.

Each element has a serial number, which is exactly equal to the number of protons in the nucleus of the atom of the element. This serial number is called atomic number. In the periodic table, the elements are arranged according to their atomic numbers, with the smallest one in the first place. One row in the table is called period and one column is called family.

The distribution and properties of atoms' extranuclear electrons have obvious regularity. Scientists arrange elements with the same number of electrons in the same row and elements with the same number of electrons in the outermost layer of the same column.

The periodic table of elements has seven periods, 16 families. Each row is called a period, and each column is called a family (family VIII contains three columns). These seven periods can be divided into short-term (1, 2, 3) and long-term (4, 5, 6, 7). * * * There are 18 families, and each column from left to right counts as a family. For example, hydrogen belongs to 1 group element and helium belongs to 0 group element.