How to judge the strength of the polarity of a covalent bond

The positive valence is the one who loses electrons, and the negative valence is the one who gains electrons. Polarity, looking at the two elements that make up the compound, the farther apart they are in the periodic table, the more polar they are. This is the easiest and most practical way to judge against high school.

But to solve more difficult problems, you need more in-depth knowledge.

The strength of the polarity of the covalent bond can be judged relative to the atomic mass and the number of charges.

According to the difference in the electronegativity of the atom, the greater the difference, the stronger the polarity. Molecular polarity can be seen in terms of dipole distance.

Judging by the size of the atomic radius, the smaller the atomic radius, the stronger the covalent bond.

HF is greater than HBR

The polarity of the <> chemical bond is determined by the difference in electronegativity of the atoms. In chemical bonds, the greater the difference in electronegativity between atoms, the stronger the polarity of the chemical bonds. Chemical bonds with strong polarity are generally more stable and harder to break than less polar ones.

To determine the polarity of a chemical bond, the following methods can be used:

Contrast the electronegativity of atoms: The more electronegative the atom, the more likely it is to form a polar chemical bond. The electronegativity of an atom can be compared using ortho-ion electronegativity (Pauling Scale) or density functional theory (DFT) indicators.

Calculate polarizability: Polarizability is a measure of how unevenly the electron density is distributed in a chemical bond. The greater the polarizability, the stronger the polarity of the chemical bond.

Calculate the dipole moment: The dipole moment refers to the rotation of the electron density in a chemical bond. The greater the dipole moment, the stronger the polarity of the chemical bond.

Calculate the electrotransfer rate: The electrotransfer rate refers to the degree to which electrons are transferred in a chemical bond. The greater the rate of electrotransfer, the more polar the chemical bond will be.

It is judged according to the strength of the redox property of the element, that is, the degree of the tung cherry tree, which is prone to electron loss.

For example, N2, SiC, Cf4, CS2, and CCl4 are diatomic molecules with non-polar bonds.

Cf4, C2 and Ccl4 groups C are all normal, the structure is the same, F, Cl and S oxidation are arranged from strong to weak, so the polarity of Cf4, Ccl4 and C2 chemical bonds is weakened in turn.

Both of them are carbon group elements in SiC, and their oxidation is similar, so the polarity of their chemical commification bonds is very weak.

The strength of the chemical bonds of CF4, CCL4, CS2, SiC and N2 decreases in turn.

ch4,nh3,hf,sih4,h2o

H+ showed normal valence, and the oxidation of F, O, N, C, and Si decreased sequentially, so the oxidation of Hf, H2O, NH3, CH4, and SiH4 chemical bonds decreased sequentially.

The polarity of a covalent bond arises because the electronegativity of the two atoms forming the bond is not the same.

Atoms with high electronegativity "pull" the shared electron pairs towards their side, causing an uneven distribution of charges. This forms a set of dipoles, and such bonds are polar bonds. An atom with high electronegativity is a negative dipole and is denoted as δ-; The atom with low electronegativity is a positive dipole and is denoted as δ+.

The degree of polarity of a bond can be measured by the difference between the electronegativity of two atoms. The difference between to is a typical polar covalent bond. When two atoms are exactly the same (and of course, the electronegativity of Chano is also exactly the same), the difference is 0, and the atoms form non-polar bonds with each other.

Conversely, if the difference is exceeded, there will be no covalent bond between the two atoms, but an ionic bond.

Polar covalent bonds:The covalent bond formed by the sharing of electron pairs between different kinds of atoms, and the electrons are obviously biased towards the atoms with strong non-metallic properties, which is a polar covalent bond, referred to as a polar bond. In polar bonds, one end of the atom of the element with relatively strong non-metallic properties is negative; Non-metallic properties are relatively defeated, and the atoms of weaker elements are electropositive at one end.

In polar bonds, the greater the difference in the non-metallic properties of the bonding elements, the more obvious (stronger) the polarity of the covalent bond; The smaller the non-metallic nature or difference of the bonding elements, the less pronounced (weaker) the polarity of the covalent bond.

There are 3 ways to determine whether a covalent bond is polar or non-polar:

If the bonding atom is an atom of the same element, a non-polar bond is formed, otherwise a polar bond is formed;

If the bonding electron pair is not biased towards a certain bonding atom, a non-polar bond is formed, otherwise a polar bond is formed;

If the bonding atom is not electrically conductive, a non-polar bond is formed, otherwise a polar bond is formed.

Without considering the delocalized and coordination keys, the method and method are essentially equivalent.

The method cannot be used as a basis for judgment, because an atom can form multiple covalent bonds with the same atom and different kinds of atoms at the same time, and a polar bond can be formed between an atom and different kinds of atoms, thus showing electricality, and a non-polar bond is formed between it and the same atom, so the atom with electrical property can form a non-polar bond, that is, the method is wrong.