Covalent bonds bind the different atoms collectively as the electrostatic attraction among the positively charged nuclei, and the negatively charged electrons are more significant as compared to the repulsion among the identical charged nuclei.
The intensity of a covalent bond is defined by the force needed for breaking the bond, which means the total energy required to divide the covalently bonded atoms. A covalent bond is organized based on the number of shared electrons pair, the bond polarity, and the coordination of the atoms. The covalent bonds are classified into three types of bonds depending on the shared electron pairs.
When a pair of electrons or a total of 2 electrons are shared among the atoms, it forms a single covalent bond, also identified as simply a single bond. When 2 electron pairs or a total of 4 electrons are shared among the atoms it forms a double covalent bond, also identified as a simple double bond. When 3 electron pairs or a total of 6 electrons are shared among the atoms it forms a triple covalent bond, also identified as a simple triple bond.
Depending on the polarity of the bond and the coordination of the atoms, covalent bonds are classified into three categories:. A polar covalent bond formation occurs if the sharing atoms possess a notable difference in the electronegativities. Thus, the bonded electron pair is pulled toward the higher electronegative atom, making the atom somewhat negative, and the opposite atom becomes slightly positive.
When the bond is a polar covalent bond, the sharing of electrons between the atoms is unequal, as they are greatly pulled to one nucleus as compared to the other. Further, the atom that pulls the electrons in its direction with a greater influence is regarded as highly electronegative. This charge is known as a partial charge, also termed as a dipole that is an essential characteristic of the water molecule and is also considered for several of the features of water.
You can also read out the article on the polarity of H2O. When the difference in the electronegativity among the participating atoms is zero, it leads to the formation of a non-polar covalent bond. Check out the article on the polarity of Cl2. A coordinate or dative covalent bond is formed when the shared electron pairs are gained from one of the participating atoms. Covalent bonds are accountable for the overall function of stable covalent compounds.
The properties of a covalent bond are listed below. The covalent bonds connecting different atoms can be classified as single, double, or triple bonds. Covalent bonds are strong and stable, and high energy is needed for bond breaking to carry out the reaction. They are not soluble in water, which is a polar solvent.
Still, they are soluble in benzene, which is a non-polar solvent. The electrostatic attraction binds the two oppositely charged ions collectively and is termed the ionic bond.
The chemical bond is formed among two participating atoms by the total shift of one or more electrons from one atom to the other, thereby achieving their inert gas configuration. There are essentially three methods for two atoms to link to spend energy and acquire stability.
One approach is gaining or losing electrons to achieve octet configuration. The bond produced by this type of method is called an ionic bond. This class of bond is made when one atom takes electrons, whereas the other atom gives electrons from its valence orbital. The ionic bonded molecules possess a strong force of attraction among cations and anions, and the following characteristics are seen:. The charge is separated in ionic bonded molecules, and thereby they are the most reactive of all the bonds in the given condition.
When dissolved in water or in the molten state, the ionic bonded molecules conduct electricity. This is because of the ions, which serve as charge carriers. The type of a bond among two participating atoms can be estimated by calculating the electronegative value among the atoms involved in bonding. Since we know the concept of covalent and ionic bonding, let us now move on to understand the reason behind the covalent bonding in hydrogen fluoride.
Hydrogen fluoride is a polar covalent bond. The intermediate of an ionic and a covalent bond is considered a polar covalent bond. The polar covalent bond is depicted by an arrow. Electronegativity is described as the capacity of an atom to pull electrons towards itself. In a hydrogen fluoride molecule, the electronegativity of hydrogen is 2. Thus, the electronegativity difference is 1. HF is a polar covalent compound. This particular resource used the following sources:. Skip to main content.
Advanced Concepts of Chemical Bonding. Search for:. Bond Polarity. Key Points The unequal sharing of electrons within a bond leads to the formation of an electric dipole a separation of positive and negative electric charges.
To determine the electron sharing between two atoms, a table of electronegativities can determine which atom will attract more electron density. Atoms that tend to strongly attract electrons have a high electronegativity, relative to atoms that have a relatively low tendency to attract electrons towards themselves. The modern electronegativity scale was devised by Linus Pauling in and, in the Pauling scale, atoms in the periodic table vary in electronegativity from a low of 0.
In the molecule HF, the electronegativity of the hydrogen is 2. This difference leads to the profound polarization of the HF covalent bond which is apparent in the electrostatic potential map. Polarizations of covalent bonds also occur in more complex molecules. In water, the oxygen has an electronegativity of 3. Because of this, each of the H-O bonds is polarized with greater electron density towards the oxygen.
Within the molecule, H 2 O, the effect of this polarization becomes apparent in the electrostatic potential map, as shown in Figure 3. The end of the molecule with the oxygen has a high electron density and the hydrogen ends are electron deficient.
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