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