Types of chemical bond
- Electrovalent or ionic bond
- Covalent bond
- Coordinate bond
Ionic bond and factors affecting it
- It is formed by transfer of electrons.
- It is formed between metal and no metal.
- In it metal always loses electrons and non-metal always accepts electron.
- Sodium chloride
- Calcium Fluoride
Factors affecting the formation of ionic bond
The factors are:
- Low ionization energy
- High electron affinity
- High lattice enthalpy
- Low ionization energy: The metals with low ionization energy favor the formation of ionic bond. As lower is the ionization energy more readily it will lose electrons.
- High electron gain enthalpy: The non-metal participating should have high electron gain enthalpy because more it will have attraction, for upcoming electron more readily the bond will be formed.
- Lattice enthalpy: It is the amount of energy needed to break one mole of bonds into its constituents, or the energy released when constituents combine to form on 1 mole of a compound. More is the lattice energy, more stable is the bond formed. All the compounds in which ionic bond is present are called as ionic compounds.
General properties of ionic compounds:
- Physical state: They form definite pattern that is crystal lattice. Crystal lattice is 3D arrangement of cation and an anion.
For example, in NaCl crystal due to crystal formation they all are solids due to strong bonding between constituents.
- Melting and boiling point: They have high melting and boiling points because of strong attraction between constituents.
- Solubility: We know like dissolves like. So, polar compounds are soluble in polar solvents. Now, ionic compounds have a charge that is they are polar. Therefore, they will dissolve in polar solvents like water. So, all ionic compounds are soluble in polar solvents and insoluble in organic solvents.
- Electrical conductivity: It is due to free movement of free ions when ionic compound is dissolved in water. When dissolved they break into ions and conduct electricity.
- Non directional in nature: When we are talking of directions in 3D structure, we are talking about 3 coordinate .So, in NaCl or any other ionic compounds the ion can take place in any direction .There direction is not fixed. Therefore, they are non-directional in nature.