What are the characteristics of the second cycle of chemistry

The number of electron layers is the same in the same period;

From left to right, the number of electrons in the outermost shell increases, the atomic number increases, and the atomic radius decreases gradually...

The number of electron layers outside the nucleus is two layers.

In the periodic table, each horizontal row is called a period, the first period is the first horizontal row, and the second period is the second horizontal row.

The periodic table has 7 periods and 16 families. Each horizontal row is called a period, and each vertical row is called a family (group VIII contains three columns). These 7 cycles can be divided into short cycles and long cycles).

There are 16 families, one in each column from left to right (except for VIII).

Elemental property changes:

The position of an element in the periodic table not only reflects the atomic structure of the element, but also shows the law of gradual change in the properties of the elements and the internal connections between the elements. It constitutes a complete system and is known as one of the important milestones in the development of chemistry.

In the same period, from left to right, the number of electrons outside the nucleus of the element is the same, the number of electrons in the outermost shell increases sequentially, and the atomic radius decreases (except for group 0 elements). The ability to lose electrons is gradually weakened, the ability to gain electrons is gradually increased, the metallicity is gradually weakened, and the non-metallic ability is gradually enhanced. The highest positive oxidation number of an element increases from left to right (except for those without positive valence), and the lowest negative oxidation number increases from left to right.

In the periodic table, each horizontal row is called a period, and the number of electrons in the outermost shell of their atoms increases sequentially, and the number of electron layers is the same.

Each cycle is the first transverse line, there are two elements, hydrogen and helium, their proton numbers are , electron numbers are also , and there is only one electron shell outside the nucleus;

The second period is the second transverse line, there are eight elements, the number of protons of their atoms ranges from 3 to 8, there are two electron shells outside the nucleus, the first shell has two electrons, and the number of electrons in the second shell increases from one to eight.

The periodic table of chemical elements is a list of chemical elements sorted from smallest to largest according to their atomic number. The list is generally rectangular in shape, with spaces in the period of some elements, so that elements with similar characteristics are grouped into the same family, such as alkali metal elements, alkaline earth metals, halogen elements, rare gases, etc.

This results in the periodic table forming an elemental partition with seven primary families, seven secondary groups, and zero families. Because of its ability to accurately ** the properties of various elements and the relationships between them, the periodic table is widely used in chemistry and other scientific fields as a useful framework for analyzing chemical behavior.

Each horizontal row is called a cycle, and each vertical row is called a family. These 7 cycles can be further divided into short cycles, long cycles) and incomplete cycles (7). There are 16 families, which are divided into 7 main families (a-a), 7 sub-families (b-b), one sub-family (including three vertical rows), and one zero family. Hope to adopt.

From left to right, the metallicity of the right element gradually decreases, and the non-metallic property gradually increases, so the element with the strongest ability to replace hydrogen in the acid is Na.

The element with the most stable chemical and apochemical properties is group 0 element, and the third period element is ar.

The element that can make semiconductors is silicon, and the name is silicon;

The most acidic compound of the hydrate of the most ** oxide corresponds to the element Cl, and the corresponding acid is HCO4

The most basic compound is NaOH with the chemical formula NaOH;

Amphoteric hydroxides in the third cycle are Al(OH)3

The atomic radius of the element of the same period decreases gradually from left to right, and the largest atomic radius is sodium staring;

So the answer is: na; ar；Silicon; hclo4

naoh；Al(OH)3 sodium

1.A classification of the elemental leucin in the periodic table. A transverse line of a series of elements with the same number of electrons in increasing atomic order is a circumferential period.

From left to right, the metallicity of the elements of the same period gradually decreases, and the non-metallicity gradually increases. 2.Refers to a series of elements that have the same number of electron layers and are arranged in the order of increasing atomic number.

There are seven horizontal rows in the periodic table, which is seven cycles. Clause.

The first, second and third cycles are called short cycles; Clause.

The fourth, fifth, sixth, and seventh cycles are called long cycles; Generally, each cycle begins with an active metallic element, gradually transitions to an active non-metallic element, and ends with a noble gas element.