Why is it that the larger the number of electrons in the outermost shell of an atom of the same peri

In the same period, with the increase of the number of nuclear charges, the number of electrons in the outermost shell increases, and the number of electrons increases, there is a tendency to increase the radius of the atom, but the number of electron layers remains unchanged, the positive charge of the original belt of the nucleus also increases, the gravitational force on the electrons outside the nucleus increases, and there is a tendency to reduce the radius of the atom.

If the number of electron layers is different, it is not this conclusion Hope you, o( o thank you.

The radius of the atom of the same period from left to right gradually decreases:

1. The radius of the atom is mainly determined by the volume of the electron cloud, and the volume of the nucleus accounts for almost negligible proportion of the whole atom. It is not that the radius of an atom with more electrons is necessarily larger, because when the nuclear charge increases to greater than eight, the reduction of the radius of the nucleus becomes stronger and stronger, which has exceeded the increase in the radius of the electron shell.

2. There is a certain rule in the electron arrangement of elements in the same period, for example, there is only one layer (or two or three layers......electrons and increasing atomic number from left to right. With the increase of atomic number, the gravitational pull of the electron cloud crescendos, and the increase in the volume of the electron cloud is not obvious, so it is manifested that the electrons are attracted closer to the nucleus by the nucleus, and the volume of the electron cloud decreases, so the atomic radius becomes smaller and smaller.

3. With the increase of the atomic number of atoms in the same period, the number of their nuclear charges increases, that is, the number of protons increases, and the binding force of the nucleus on the electrons outside the nucleus increases, and the closer the electrons are to the nucleus, the smaller the radius.

4. Atomic radius is one of the parameters that describe the size of an atom. According to different scales and measurement methods, atomic radius is defined differently, the common ones are orbital radius, van der Waals radius (also known as paradigm radius), covalent radius, metal radius, etc. The atomic radius of the same atom can vary greatly depending on the definition, so the data** used when comparing the relative sizes of different atoms must be consistent.

5. The atomic radius is mainly affected by three factors: the number of electron layers, the number of nuclear charges and the number of electrons in the outermost shell. Generally speaking, the greater the number of electron shells, the smaller the number of nuclear charges, the lower the number of electrons in the outermost shell, and the larger the atomic radius. This also makes the atomic radius have a clear periodic degeneration law on the periodic table.

Because the number of nuclear charges of atoms in the same period increases with the increase of atomic number, that is, the number of protons increases, then the binding force of the nucleus to the electrons outside the nucleus increases, and the closer the electrons are to the nucleus, the smaller the radius.

The atomic radius is mainly affected by two factors: the number of electron layers and the number of nuclear charges. Generally speaking, the greater the number of electron layers, the smaller the number of nuclear charges, and the larger the atomic radius, which also makes the atomic radius have an obvious periodic degeneration law on the periodic table.

The atomic radius has a great influence on the chemical properties of the element, so the study of the atomic radius has great significance and value in the development of chemistry.

Isoperiod atomic radius magnitude rule:

If the nuclear charge increases by 1 from sodium to magnesium, the nucleus increases a certain force on each electron outside the nucleus, and the atom tends to shrink, while the electron outside the nucleus also increases by one electron, and the atomic radius tends to increase because the electron movement occupies a certain space.

The atomic radius of sodium is greater than that of magnesium, which indicates the effect of the increased nuclear charge on the reduction of the atomic radius. Thus, the atoms of the co-periodic elements gradually decrease from left to right (except for noble gases).

The atoms of the synperiodic elements gradually decrease from left to right (except for noble gases).

In general, the higher the number of electron layers, the smaller the number of nuclear charges, and the greater the atomic radius. This also makes the atomic radius visible on the periodic table.

The law of periodic degeneration.

For example, compare the radius sizes of sodium and magnesium. If the charge of a nuclear charge increases by 1 from sodium to magnesium, its nucleus increases a certain effect on each electron outside the nucleus.

force, the atom tends to shrink, and the electron outside the nucleus also increases by one electron, and the radius of the atom tends to increase because the electron moves to occupy a certain space.

Add. Experiments have shown that the atomic radius of sodium is greater than that of magnesium, which indicates the effect of the increased nuclear charge on the reduction of the atomic radius.

The effect of increasing the subradius.

(2) The main group elements of the same period, from left to right, increase with the atomic number.

The number of electrons of the main group elements in the same period is the same, while the effective nuclear charge z* increases significantly from left to right, and z* increases significantly, while the secondary group element z* does not increase significantly.

The transition element z* increases slowly, and the atomic radius decreases more slowly, although the nuclear charge increases more, but up. (3) The shielding effect of the same group of elements increases from top to bottom, and the atomic radius decreases accordingly, and the atoms of the adjacent two elements increase by an electron inner shell in turn, resulting in an insignificant increase in the effective nuclear charge.

The magnitude of the atomic radius is mainly determined by the number of electrons outside the nucleus and the effective nuclear charge (z*) The effective nuclear charge (z*) is equal to the atomic number (z) minus the shielding constant, i.e., z*=z-.

1) The effective nuclear charge increases with the increase of atomic number and changes periodically.

Elements of the same period have the same number of electron layers, and the larger the atomic number, the stronger the attraction to the electrons outside the nucleus, and the smaller the atomic radius.

1. In the same period, the number of electron layers remains unchanged, and the influence of the number of layers on the radius can be ignored 2. With the increase of atomic number, the outermost electrons increase, and the repulsion between electrons increases, resulting in an increase in the atomic radius.

3. As the number of atoms increases, the number of nuclear charges increases, and the attraction of the nucleus to the outermost electrons increases, causing the electron cloud to shrink inward and the atomic radius to decrease.

4. In contrast, the effect of Article 3 is greater than that of Article 2, so in the same period, as the atomic number increases, the atomic radius decreases.

This is the case when comparing the same main family, the number of atomic and electronic layers of the elements of different main families is not necessarily the larger the radius is not necessarily the greater the number of atoms and electrons of different main families;

It seems very abstract to say, so to give you the above picture: (the size of the circle represents the size of the atom) <>

The atomic radius of Li is larger than that of Cl, although Cl is one layer more than Li.

Protons in the nucleus are positively charged, and the more protons there are, the stronger the attraction; It is related to the valence layer structure, if the stable state is reached, the orbital is full or semi-full, it is difficult to gain and lose electrons, such as noble gases and transition metals. In addition, the more electrons in the outermost shell, the easier it is to gain electrons and vice versa. The smaller the radius of the atom, the easier it is to gain electrons, and vice versa.