Ionic bonds are characterized by the complete transfer of electrons from one atom to another, resulting in the formation of two charged particles known as ions, which are held together with the help of electrostatic forces. In this ScienceStruck article, learn about this intriguing occurrence in chemistry where atoms of different elements combine to form a new substance.
Chemistry is fascinating, and it is present everywhere around us, be it the beautiful raindrops on your windowpane, sweet sugars in the fruits, or the salt that makes your food tastier. Talking about salt, have you ever wondered how sodium and chlorine combine to form a salt (sodium chloride)? Well, it is due to a process of bond formation known as ionic bonding.
Basic Concepts in Chemical Bonding
All the chemical compounds are formed due to various combinations of constituent elements. Atoms of the same or different elements are combined by various chemical bonds in order to keep the molecules together and thus, they confer stability to the resulting compounds. Chemical bonds are of various types and possess varied strengths.
1. Valence Electrons and Electronegativity
All the elements possess a certain charge, which is expressed as the number of electrons they carry in the outermost or valence shell of their orbit. These electrons are termed as valence electrons, and they play a key role in bond formation. The electronegativity of every element depends on the number of valence electrons it carries. Owing to the fact that each element will have a different number of valence electrons, they can exhibit different number of valence states.
2. Why are Chemical Bonds Formed?
The purpose behind the formation of chemical bonds of any kind is given by the octet rule, which states that it is the natural tendency of the atoms of elements with lower atomic numbers (less than 20) to attain octet configuration, which is nothing but 8 electrons in their outermost shell. Thus, these atoms are very eager to combine with other elements to attain the configuration of the nearest noble gas. Why? Well, it’s simply because noble gas configuration is the most stable.
3. Types of Chemical Bonds
These elements form a bond by either donating, accepting, or sharing electrons. This is the basic principle of chemical bonding. The most common types of chemical bonds include:
- Ionic bond
- Covalent bond
- Metallic Bond
While the sharing of electrons by atoms forms covalent bonds, the transfer or electrons from one atom to another forms ionic bonds. Here we will discuss in detail the various aspects of ionic bonding.
Explanation with an Example
Ionic bonding is nothing but a type of chemical bond formation that involves complete transfer of electrons from one atom to another. When the atoms lose or gain electrons, they become differentially charged ions or oppositely charged ions. The charged ions are then attracted towards each other due to the electrostatic force, which brings the oppositely charged ions together, resulting in the formation of an ionic bond.
The most common example of ionic bonding is the formation of sodium chloride in which an atom of sodium combines with a chlorine atom.
Let us have a look at the electronic configurations of each.
Sodium (Na) : 2,8,1 and Chlorine (Cl) : 2, 8, 7.
Thus, we see that an atom of chlorine requires only one electron to attain the configuration of the nearest noble gas, i.e., Argon (2,8,8). An atom of sodium, on the other hand, requires to get rid of the single electron in its outermost shell to acquire the configuration of the nearest noble gas, i.e., Neon (2,8).
In such a scenario, the sodium atom donates its outermost electron to the chlorine atom, which requires only one electron to attain octet configuration. The sodium ion becomes positively charged due to the loss of an electron, whereas the chloride ion becomes negatively charged due to gain of an additional electron. The oppositely charged ions, thus formed, are attracted to each other and result in the formation of an ionic bond.
The presence of ionic bonds affects the chemical and physical properties of the resulting compounds. There exist several prominent characteristics of ionic bonds and here is a list of the same.
» Owing to the fact that metals tend to lose electrons and non-metals tend to gain electrons, ionic bonding is common between metals and non-metals. Hence, unlike covalent bonds that can only be formed between non-metals, ionic bonds can be formed between metals and non-metals.
» While naming these compounds, the name of the metal always comes first and the name of the non-metal comes second. For instance, in case of sodium chloride (NaCl), sodium is the metal, whereas chlorine is the non-metal.
» Compounds that contain ionic bonds readily dissolve in water as well as several other polar solvents. These bonds, thus, have an effect on the solubility of the resultant compounds.
» When ionic compounds are dissolved in a solvent to form a homogeneous solution, the solutions tends to conduct electricity.
» Ionic bonding has an effect on the melting point of the compounds as well, as such compounds tend to have higher melting points, which means that these bonds remain stable for a greater temperature range.