What are Chemical Bonds?
Before getting into our topic of the Polar Covalent bond, let’s have a thorough introduction to chemical bonding and its importance in our daily lives. As you all know, Molecules come into existence with the combination of atoms that form chemical bonds with one another.
Chemical bonding is almost everywhere. A chemical bond is a result of seeing or touching anything in our daily life. The air we breathe, the food we eat, the clothes we wear, and so on the result of one or more chemical bonds. The world we live in is not generally composed of isolated atoms; instead, it is composed of molecules formed from chemical bonds. The strong force that holds together constituent particles, atoms, ions, or molecules in a chemical species is known as “Chemical Bonds.”
Ionic Bonds and Covalent Bonds are broad sections of chemical bonding. You can further classify the Covalent Bond into Polar and Non-Polar Covalent Bond.
Various types of bonds need further discussion in detail, and the key to their formation is the difference in electronegativity between the two atoms involved in the bond.
Ionic bonds create when two ions join together by the attraction of opposite electrostatic charged particles. It is a compelling attraction between ions with a formal charge bond, also known as an ionic bond. An ionic bond with sharing of an electron to another needy atom.
Let discuss the ionic bond in the given instance of Sodium chloride (NaCl). The sodium atom has a floating electron in its outer orbit shared with the needy chlorine atom. When the difference between Sodium and Chlorine is more significant than 2, Chlorine will steal an electron from Sodium. It is because Chlorine craves another electron, while Sodium seeks to eliminate one. Everyone benefits as a result. As a result, a positively charged sodium ion (Na+) and a negatively charged ion of Chlorine are formed (Cl-).
Difference in Electronegativity > 2
The Difference is 2.1
Electrons are captured and distributed. If the electronegativity difference between two atoms is less than 1.7, then no electron stealing takes place, but rather both atoms cordially share their two electrons. So, the electron from one atom feels the nucleus attraction, and so does the electron from the other atom. Eventually, both atoms form friendly sharing relationships, resulting in a covalent bond between them.
Chemical bonds can be easily categorized into polar and non-polar bonds. The significant difference lies in the arrangement of electrons in the bonds.
Polar Covalent Bond
Let’s first talk about the Polar bond. It is one of the covalent bonds in which two atoms share unequal numbers of electrons, forming the bonds between them. These partially charged atoms respond due to electrostatic forces. Such electrostatic forces among positive and negatively charged ions create ionic bonds.
Which Elements form Polar Covalent Bond?
Various non-metallic elements tend to join together in Polar bonds. For instance, forming water, carbon dioxide, and hydrochloric acid molecules results from Polar bonding. Amines and peptides are other compounds containing Covalent Polar Bonds.
Non-metallic atoms combine with different electronegative forces to form a Covalent bond. A Covalent, polar bond is another method of sharing paired electrons as they share an even number of electrons due to the electronegative energy. It involves paired electron sharing being closer to the nucleus, whichever has the higher electronegativity.
Illustration: Polar covalent bond
One molecule of oxygen makes a double covalent bond in water with two molecules of hydrogen. In other instances, one atom of hydrogen forms a polar covalent bond with one chlorine atom in the hydrochloric acid. Carbon dioxide has one atom of carbon combined with two atoms of oxygen.
Polar Covalent Bond Formation
Suppose the electronegativity difference between the atoms is not significant enough to cause ionization but is at least 0.5, as with hydrogen and Chlorine. In that case, the Chlorine will hold the electron rather than entirely take it. It results in a covalent bond. As a result of the tiny electron surplus, the more electronegative atom in a polar covalent bond draws the electron density towards itself. Such atoms are partially negative ions that you can represent with the symbol Delta minus. Conversely, the atom is somewhat electron-deficient and thus partially positive, or Delta + when an electron leaves its orbit for another atom.
Non-Polar Covalent Bond and its Formation
You can Non-Polar Covalent in the compound if the electronegativity difference is smaller than 0.5. You can quickly notice the distribution more or less evenly or precisely evenly in the shared electrons in a non-polar covalent bond, in the case of two atoms of the same element. Thus, there will be no partial charges on the atoms. Aside from unusual events such as metallic bonding, these are the primary ways atoms join one another.
How to identify the nature of a bond
Remember that by comparing the electronegativities of two elements, you may determine the type of bond that will form between them.
- If the difference is meagre, less than 0.5, the bond will be a non-polar covalent bond in which the electrons equally distribute.
- A Polar Covalent bond, on the contrary, has electronegativity between 0.5 and 1.7, where the atom has shared electrons, but one atom holds them more strongly.
- If it is greater than 2, one atom will forcibly take an electron from the other, resulting in ions connected by an ionic bond.
Nonpolar Covalent Bond: <0.5
Polar Covalent Bond: between 0.5 – 1.7
Ionic bond: >2
Factors to Identify the Polar Covalent Bond
Some properties help in the identification of covalent or ionic compounds. You need to look at the details for the determination of the covalent or ionic bond.
- Ionic compounds are in the composition of most crystals because they use the crystal lattice structure to balance the attraction between opposite and repulsion between similar ions. Crystal examples of covalent or molecule compounds include sugar and diamond.
- Covalent compounds have less resistance to heat, and therefore have lower melting and boiling points than ionic compounds.
- Covalent compounds have much softer and flexible mechanical properties compared to brittle and hard ionic compounds.
- Ionic compounds conduct electricity or easily dissolve into water, while covalent bonds lack such a capacity for electrical conductivity. Ionic compounds dissolve into ions, leaving charged ions that are conducive to electricity. In contrast, covalent bonds dissolve into molecules.