Difference Between Ionic, Covalent and Metallic Bonds

Formation of Ionic Bond

The formation of an ionic bond occurs when one atom has a significantly higher electronegativity than the other. The atom with higher electronegativity attracts the valence electrons of the other atom more strongly, causing the transfer of electrons. This transfer results in the formation of ions with opposite charges. The positively charged ion is called a cation, and the negatively charged ion is called an anion. These ions are then attracted to each other due to the electrostatic forces of attraction, forming an ionic compound. 

Example: Sodium (Na) donates an electron to chlorine (Cl), forming Na+ and Cl- ions. The strong electrostatic attraction between these oppositely charged ions creates an ionic bond.

Ionic Bond

Formation of Covalent Bond 

Covalent bonds are formed through the mutual sharing of electrons between atoms. Atoms that participate in covalent bonding have similar electronegativities, leading to a more equal sharing of electrons. The shared electrons occupy the outermost energy levels (valence shells) of the atoms, resulting in the formation of a stable electron configuration for both atoms. This shared electron pair forms a covalent bond, holding the atoms together in a molecule.

Example: Water (H2O), Methane (CH4).

Covalent Bond

Formation of Metallic Bond

Metallic bonds form within metals due to the delocalization of valence electrons. In a metallic lattice, each metal atom contributes its valence electrons to a common electron cloud, creating a "sea of electrons." This delocalization allows the valence electrons to move freely throughout the lattice, leading to high thermal and electrical conductivity in metals.

Example: Copper (Cu), Iron (Fe)

Metallic Bond

Properties of Ionic, Covalent and Metallic Bonds

Properties of Ionic Bonds

Formation of Ions: Electrovalent bonds involve the complete transfer of electrons from one atom to another, resulting in the formation of positively charged cations and negatively charged anions.

High Melting and Boiling Points: Electrovalent compounds generally have high melting and boiling points due to the strong electrostatic forces between ions. The breaking of electrovalent bonds requires a substantial amount of energy.

Solubility in Polar Solvents: Electrovalent compounds tend to be soluble in polar solvents like water. The polar nature of the solvent allows for the dissociation of the ionic compound into its constituent ions, which can interact with the polar solvent molecules.

Conductivity: In the molten state or when dissolved in water, electrovalent compounds can conduct electricity. The movement of ions enables the flow of electric current.

Crystal Lattice Structure: Electrovalent compounds often form a three-dimensional crystal lattice structure. The repeating pattern of alternating positive and negative ions maximises the attractive forces between ions.

Properties of Covalent Bonds

Electron Sharing: Covalent bonds involve the sharing of electrons between atoms, resulting in the formation of a shared electron cloud.

Variable Bond Strength: The strength of covalent bonds can vary depending on factors such as bond length and bond energy. Shorter and stronger bonds require more energy to break.

Lower Melting and Boiling Points: Covalent compounds generally have lower melting and boiling points compared to electrovalent compounds. The intermolecular forces between molecules are weaker than the strong electrostatic forces in ionic compounds. 

Solubility in Nonpolar Solvents: Covalent compounds are often soluble in nonpolar solvents, such as hexane or benzene, which do not interact strongly with the covalent bonds.

Poor Conductivity: Covalent compounds are generally poor conductors of electricity in any state since they lack freely moving charged particles. Exceptions include certain covalent compounds that dissociate into ions in solution or covalent compounds with mobile charge carriers, such as graphite.

Properties of Metallic Bonds

Delocalized Electrons: Metallic bonds involve the delocalization of valence electrons, which are free to move throughout the metallic lattice.

High Thermal and Electrical Conductivity: The delocalized electrons in metallic bonds allow for efficient transfer of heat and electrical energy.

Malleability and Ductility: Metallic bonds contribute to the malleability and ductility of metals, as the delocalized electrons can adjust and flow under stress.

Lustre: Metallic bonds give metals their characteristic shine or lustre due to the reflection of light by the free electrons. Variable strength: The strength of metallic bonds can vary depending on factors such as the size and arrangement of metal atoms.

Difference Between Ionic Covalent and Metallic Bonds

Summary

An ionic bonds involve the complete transfer of electrons from one atom to another. This results in the formation of oppositely charged ions that are held together by strong electrostatic forces. Ionic bonds typically occur between atoms with a significant difference in electronegativity. On the other hand, covalent bonds involve the sharing of electrons between atoms. This sharing creates a shared electron cloud that holds the atoms together. Covalent bonds generally occur between atoms with similar electronegativity.  Metallic bonds are unique to metals and involve the delocalisation of valence electrons throughout a metallic lattice.