There is a problem with the period of the element 5

The 4th cycle 19 and 36 are all the same number of electron layers, of which the new electrons of 21 and 30 are all in the third layer.

But there are exceptions, and the Pd (palladium) of the 5th cycle has only four electron shells.

The arrangement of the 19th king is 2,8,8,1

The arrangement of the 20th CA is 2, 8, 8, 2

The arrangement of 21 and 30 is generally 2,8,9,18,2; But where cr is 2,8,13,1 and cu is 2,8,18,1

31 36 of the elements of the new electrons again to the fourth period.

The arrangement of kr 36 is 2, 8, 18, 8

It is recommended that you take a look at the law of electron configuration outside the nucleus.

From the fourth period onwards, the law of increase in electrons outside the nucleus of an element is not as simple as before. For example:

mg in the third cycle is 2,8,2, then al is 2,8,3;

However, in the fourth cycle, Ca is 2,8,8,2, but Sc (scandium) is 2,8,9,2, and Ti is 2,8,10,2, and the law of electron increase from elements 21 to 30 is more complicated, involving the knowledge of energy level interlacing, for example, V (vanadium) is 2, 8, 11, 2, but Cr (chromium) is 2, 8, 13, 1, and so on until Zn is 2, 8, 18, 2, until Ga is officially "connected" to the law of Ca becomes 2, 8, 18, 3, so the number of electrons in this period is 4

Element 19k has 4 layers of electrons: 2, 8, 8, 136 krypton also has 4 layers of electrons: 2, 8, 18, 8

Nos. 19 and No. 36 are both 4 floors.

The four electrons of potassium in the 19th are 2, 8, 8, and 1 in order

Argon No. 36 is an inert gas, and the number of electronic layers is 2, 8, 18, 8, and the first layer is up to 2, the second layer is up to 8, the third layer is 18, and the 4th layer is 32.

But the reason why No. 19 is not arranged in 2,8,9 is because there are no more than 8 electrons in the outermost shell, no more than 18 in the subouter shell, and no more than 32 in the penultimate shell.

It's the same, except that the order of electrons from potassium to kr isn't what you think.

The book says that the main group elements have the same number of electron layers, and from 21-30, the middle piece is the secondary group elements (all metals) are counted separately.

The number of electronic layers on 19 and 36 is actually 4 layers, and 19 is 2 8 8 1

The number 36 is 2 8 18 8

It should be judged according to the energy level and energy layer.

Arrange elements by cycle time:

There are currently 118 elements in the periodic table, of which only 94 are currently found in nature, and the other 24 are synthesized artificially.

The 118 elements are not a collection of all the elements in the universe, although there are only 94 kinds of natural elements that we have found so far, but the universe is so vast that we know that it is not even 1%, and in the unknown universe, there may be other more mysterious and complex natural elements.

The periodic table is a list of chemical elements sorted by atomic weight from smallest to largest.

In 1913, the British scientist Mosel used cathode rays to hit metal to produce X-rays, and found that the larger the atomic order, the higher the frequency of X-rays, so he believed that the positive charge of the nucleus determined the chemical properties of the elements, and arranged the elements according to the positive charge in the nucleus (that is, the number of protons or atomic order), which became the contemporary periodic table after many years of revision.

In the periodic table, the elements are arranged in their atomic order, with the smallest coming first. A horizontal row in a table is called a period, and a column is called a family.

Secondary periodicity

Periodic table in English.

In the periodic table, the change of the elements in the p-region from top to bottom is not a strictly increasing curve, but a zigzag curve. There are two inflection points on the curve: the second cycle and the fourth cycle. According to the calculation of the relativistic effect, there will be a third inflection point in the sixth cycle.

Irregularities in the second cycle.

The reason is that there are few electrons in the inner shell of the second period (only 1s2) and the atomic radius is very small, so the way and type of bonding of the elements in the second period are very different from those in the later periods. For example, the nitrogen group element (A), pentachloride in the first blind stage of the 3rd and 6th weeks has been produced, but NF5 is not present, let alone molecules such as NC5. For example, the difference in the maximum coordination number of carbon and silicon leads to the difference in the crystal structure of carbon dioxide and silica.

The irregularity of the fourth cycle.

The p-block elements of the fourth period have just passed through the d-block, so the atomic radius does not change much compared to the third period of the homogeneous pure group. Therefore, many compounds of the fourth cycle elements are relatively unstable, such as HCO4 and HIO4 were prepared very early, but HBRO4 was only prepared in 1967, and the oxidation is the strongest among the high halogen acids (except for high fluoric acid, which is thermodynamically unstable).

First Cycle Elements: 1 Hydrogen (qīng) 2 Helium (hài) Second Cycle Yuanyou Type Element: 3 Lithium (lǐ) 4 Beryllium (pí) 5 Boron (Péng) 6 Carbon Oak (Tàn) 7 Nitrogen (Dàn) 8 Oxygen (Yǎng) 9 Fluorine (Fú) 10 Neon (Nǎi).

Third Cycle Elements: 11 Sodium (nà) 12 Magnesium (měi) 13 Aluminum (lǚ) 14 Silicon (guī) 15 Phosphorus (lín) 16 Sulfur (liú) 17 Chlorine (lǜ) 18 Argon (yà).

Fourth Cycle Elements: 19 Potassium (jiǎ) 20 Calcium (gài) 21 Scandium (kàng) 22 Titanium (tài) 23 Vanadium (fán) 24 Chromium (gè) 25 Manganese (měng) 26 Iron (tiě) 27 Cobalt (gǔ) 28 Nickel (niè) 29 Copper (tóng) 30 Zinc (xīn) 31 gallium (jiā) 32 Germanium (zhě) 33 arsenic (shēn).

The significance of the discovery of the periodic law: The periodic law reveals the fact that the properties of elements change periodically due to the increasing number of nuclear charges of the atomic atoms, and strongly demonstrates the regularity of qualitative changes caused by quantitative changes in things from natural science.

The periodic table is a concrete manifestation of the periodic law, which integrates the elements into a system, reflects the intrinsic relationship between the elements, and breaks the metaphysical view that the elements are isolated from each other. Through the study of the periodic law and the periodic table, one can deepen the understanding of the law of opposition and unity in the material world.

The periodic table provides an objective basis for the development of a theory of the structure of matter. The electronic shell structure of atoms is closely related to the periodic table, which provides clues for the development of transition element structure, lanthanide and actinide structure theory, and even for guiding the synthesis of new elements, the structure and properties of new elements.

The periodic law and the periodic table are important tools in many departments of the natural sciences, first and foremost chemistry, physics, biology, geochemistry, etc.