From Si to Pb small increase is found .
Ionization Enthalpy : -The first ionization enthalpies of group 14 elements are higher than those of the corresponding group 13 elements .
Electronegativity : -Group 14 elements are smaller in size as compared to group 13 elements that ’ s why this group elements are slightly more electronegative than group 13
Chemical properties : -
Carbon and silicon mostly show + 4 oxidation state . Germanium forms stable compounds in + 4 state and only few compounds in + 2 state .
Tin forms compounds in both oxidation states . Lead compounds in + 2 state are stable and in + 4 state are strong oxidizing agents .
Exception : -Pb4 and SnF4 are ionic in nature . Except CCl4 other tetra chlorides are easily hydrolysed by water .
Since carbon does not have d-orbitals and hence cannot expand its coordination number beyond 4
CCl4 + H2O No Reaction
SiCl4 + 4H2O Si ( OH ) 4 + 4HCl Silicic acid Allotropes of Carbon : -The three types of allotropes are – 1-Diamond 2-Graphite 3-Fullerence Diamond : -In diamond each carbon atom undergas SP 3 hybridisation . Each carbon is tetrahedrally linked to four other carbon atoms .
Graphite : -In graphite , carbon is SP 2 -hyberdized graphite has a twodimensional sheet like structure consisting of a number of hexagonal rings fused together .
Graphite conducts electricity along the sheet . It is very soft and Slippery