CBSE
Class 10 Class 12
Metals form ionic bonds when they react with non-metals. Compounds so formed are known as ionic compounds.
Ions: Positive or negative charged atoms are known as ions. Ions are formed because of loss or gain of electrons. Atoms form ion to obtain the electronic configuration of nearest noble gas, this means to obtain stable configuration.
Positive ion: A positive ion is formed because of loss of electrons by an atom. Following are some examples of positive ions.
Examples:
Sodium forms sodium ion because of loss of one electron. Because of loss of one electron; one positive charge comes over sodium.
Na → Na+ + e−
Similarly; potassium gets one positive charge by the loss of one electron.
K → K+ + e−
Magnesium forms positive ion because of loss of two electrons. Two positive charges come over magnesium because of loss of two electrons.
Mg → Mg+ + + 2e−
Similarly, calcium gets two positive charges over it by the loss of two electrons.
Ca → Ca++ + 2e−
Negative ion: A negative ion is formed because of the gain of an electron. Some examples are given below.
Examples:
Chlorine gains one electron in order to achieve stable configuration. After the loss of one electron chlorine gets one negative charge over it forming chlorine ion.
Cl + e− → Cl−
Similarly, fluorine gets one negative charge over it by the gain of one electron forming chloride ion; in order to achieve stable configuration.
F + e− → F−
Metals form ionic bonds when they react with non-metals. Compounds so formed are known as ionic compounds.
Ions: Positive or negative charged atoms are known as ions. Ions are formed because of loss or gain of electrons. Atoms form ion to obtain the electronic configuration of nearest noble gas, this means to obtain stable configuration.
Positive ion: A positive ion is formed because of loss of electrons by an atom. Following are some examples of positive ions.
Examples:
Sodium forms sodium ion because of loss of one electron. Because of loss of one electron; one positive charge comes over sodium.
Na → Na+ + e−
Similarly; potassium gets one positive charge by the loss of one electron.
K → K+ + e−
Magnesium forms positive ion because of loss of two electrons. Two positive charges come over magnesium because of loss of two electrons.
Mg → Mg+ + + 2e−
Similarly, calcium gets two positive charges over it by the loss of two electrons.
Ca → Ca++ + 2e−
Negative ion: A negative ion is formed because of the gain of an electron. Some examples are given below.
Examples:
Chlorine gains one electron in order to achieve stable configuration. After the loss of one electron chlorine gets one negative charge over it forming chlorine ion.
Cl + e− → Cl−
Similarly, fluorine gets one negative charge over it by the gain of one electron forming chloride ion; in order to achieve stable configuration.
F + e− → F−
Physical nature: Ionic compounds are solids and are somewhat hard because of the strong force of attraction between the positive and negative ions. These compounds are generally brittle and break into pieces when pressure is applied.
Melting and Boiling points: Ionic compounds have high melting and boiling points. This is because a considerable amount of energy is required to break the strong inter-ionic attraction.
Solubility: Electrovalent compounds are generally soluble in water and insoluble in solvents such as kerosene, petrol, etc.
Conduction of Electricity: The conduction of electricity through a solution involves the movement of charged particles. A solution of an ionic compound in water contains ions, which move to the opposite electrodes when electricity is passed through the solution. Ionic compounds in the solid state do not conduct electricity because the movement of ions in the solid is not possible due to their rigid structure. But ionic compounds conduct electricity in the molten state.
