NCERT Solutions for Class 11 Chemistry Chapter 3- Classification of Elements and Periodicity in Properties

This chapter deals with the significance of classification, a brief history of the development of periodic table, modern periodic law and the present form of the periodic table, periodic trends in properties of elements -atomic radii, ionic radii, inert gas radii, Ionisation enthalpy, electron gain enthalpy, electronegativity and valency. It also discusses the nomenclature of elements with atomic numbers greater than 100.

• Modern Periodic Law along with the Present form of Periodic Table

This topic explains the important analogies among the 94 naturally occurring elements revealed by Periodic Law and the modern version of the periodic table.

• Nomenclature of elements whose atomic number are greater than 100

This topic deals with the synthesis and characterization of new elements with very high atomic numbers that are so unstable that only minute quantities, sometimes only a few atoms of them are obtained.

• Electronic Configuration of Elements and the Periodic Table

In this section, the students will observe a direct connection between the elements' electronic configurations and the long form of the Periodic Table.

• Electronic Configuration and the Types of Elements: s-, p-, d-, f- Blocks

The elements of Group 1 (alkali metals) and Group 2 (alkaline earth metals) which have ns1 and ns2 outermost electronic configuration belong to the s-Block Elements. The p-Block Elements comprise the elements that belong to Group 13 to 18. The last electron added to each element of the two rows of elements at the bottom of the Periodic Table is filled in f- orbital. The elements of Group 3 to 12 in the centre of the Periodic Table are d-block elements.

• Trends in Physical Properties

This topic discusses the periodic trends concerning atomic and ionic radii, ionisation enthalpy, electron gain enthalpy and electronegativity.

• Periodic Trends in Chemical Properties

In this section, the students shall study the periodicity of the valence state shown by elements and the second-period elements' anomalous properties (from lithium to fluorine).

• Periodic Trends and Chemical Reactivity

Students shall try to explore relationships between the fundamental properties of elements with their chemical reactivity.