Ionic and Covalent Bonds: Whenever word bond to hear it means to tie something together.Chemical means we cannot separate (irreversible) by physical means. There is an attractive force which keeps two atoms together in a molecule.Atoms may attain stable electronic configuration in three different ways by losing or gaining electrons by sharing electrons.
Why Ionic and Covalent Bonds Form
Ionic and Covalent bonds form to achieve:
A. Minimum Energy and
Conditions for Formation of Ionic and Covalent Bonds
In the formation of molecules, only electrons present in the outermost shell or valence shell of atom normally participate.The electrons belonging to inner energy shell are mostly not involved in the formation of the bond.
For Covalent Bond
The combining atoms mutually contribute one, two or three electrons depending upon their requirement the bond formed.This leads the formation of single double and triple bond.
- The bond is formed between the two non-metals.
- Each combining atom must contribute at least one electron to the shared pair.
- The combining atoms should achieve the electronic configuration of the nearest noble gas atom.
- The electronegativity difference between the two atoms should be less.
For Ionic Bond
1.It is generally formed of the metals and nonmetals. The metal atom loses one or more electrons present in its valence shell and these electrons accept by the nonmetallic atom.
2.One of the species is cation and the other is an anion.By losing electrons, the metal atom changes to (positive ion) cation.Similarly, the nonmetal atom gaining the electrons, get a change to (negative Ion) anion. The oppositely charged ions attract each other. Therefore, come closer resulting the formation of the ionic bond (Electrovalent Bond).
Ionic bond possible only when one of the species must have low ionization energy and the other should have high electron affinity.
General characteristics of Ionic and Covalent Bonds
Ionic bond Characteristics
1.Because of strong interionic forces, the ionic compound has generally high melting and boiling point.
2. Ionic compounds generally dissolve in a polar solvent (like water). The ionic compound does not dissolve in an organic solvent like Benzene carbon tetrachloride because they are non-polar in nature.
3.Take part in an ionic reaction which is very fast and does not require any specific condition. For example, an aqueous solution of NaCl and AgNO3 are mixed a white precipitate of AgCl is immediately formed.
Covalent Bond Characteristics
1.The covalent compounds do not exist as ions but they exist as molecules
2.The melting and boiling points of covalent compounds are generally low. The fact that the forces between the molecules are weak.
3. Covalent Compounds generally insoluble or less soluble in water with exceptions.
4.These reactions are quite slow because energy is required to break covalent bonds.
This is about the Ionic and Covalent bonds.