Mainly c and si show tetravalency as other elements no have +4 due to inert pair effect as going down the group

Tetravalency in the Carbon Family
The carbon family, also known as Group 14 in the periodic table, includes carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead (Pb). While carbon exhibits tetravalency, not all elements in this group maintain this characteristic.
Tetravalency Explained
- Definition: Tetravalency indicates an atom's ability to form four covalent bonds.
- Carbon's Tetravalency:
- Carbon has four valence electrons.
- It can share these electrons with other atoms, forming four covalent bonds, as seen in methane (CH4).
Hybridization of Carbon
- Types of Hybridization:
- sp3 Hybridization: In methane, carbon undergoes sp3 hybridization, forming four equivalent bonds.
- sp2 Hybridization: In ethylene (C2H4), carbon uses sp2 hybridization, resulting in three sigma bonds and one pi bond.
- sp Hybridization: In acetylene (C2H2), carbon combines its orbitals to form two sp hybridized orbitals connected by a triple bond.
Tetravalency in Other Elements
- Silicon: Exhibits tetravalency similar to carbon, forming four bonds in compounds like silicon dioxide (SiO2).
- Germanium: Also shows tetravalency, but its bonding characteristics can vary.
- Tin and Lead: These elements can exhibit variable valency; while tetravalent in some compounds, they often display divalent behavior.
Conclusion
While the carbon family elements are capable of forming four bonds, only carbon and silicon consistently exhibit tetravalency in their most common compounds. Understanding these differences helps in grasping the behavior of organic and inorganic compounds.