CBSE Class 11-science Chemistry The s-Block Elements
Introduction to Group 1 Elements
The s-block elements of periodic table constitute Group 1(alkali metals).
Alkali metals are characterized by one s-electron which makes them highly reactive and forms monopositive ions.
Atomic and ionic size increases while ionization enthalpy decreases down the group.
Alkali metals are highly reactive due to large size and low ionization.Introduction to Group 2 Elements
Alkaline earth metals are the s-block elements with two electrons in the valence shell.
Atomic and ionic radii increase from Beryllium to Radium.
Ionization enthalpy and hydration enthalpy decreases from Beryllium to Radium.Anomalous Behaviour
Anomalous property of lithium and beryllium is due to its small size, high polarizing power, high ionization energy and non-availability of d-orbtials.
Similarity in properties of elements present diagonally is called diagonal relationship.
Group 1 elements have larger size and lower electrical conductivity than group 2 elements.Important Compounds of s-Block
Sodium carbonate is prepared by Solvay Process.
Sodium hydroxide is produced by electrolysis of sodium chloride in Castner- Kellner Cell.
Sodium and potassium ions participate in the transmission of nerve signals.
Magnesium ions catalyze formation as well as hydrolysis of phosphate linkages in ATP.Alkali and Alkaline Metal Compounds
Hydroxides of Group 1 are more basic than Group 2.
Halides of Group 1 are extensively hydrated than the corresponding halides of Group 2 .
Carbonates of Group 1 are thermally more stable than carbonates of Group 2.
Nitrates of both Group 1 and Group 2 is water soluble.
