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The P-Block Elements

Question
CBSEENCH11007307

Explain why silicon shows a higher covalency than carbon. 

Solution

Carbon cannot have a valency beyond four space space left parenthesis straight C presubscript 6 space equals space 1 straight s squared space 2 straight s squared space 2 straight p subscript straight x superscript 1 space 2 straight p subscript straight y superscript 1 right parenthesis
space while space silicon space can space extend space its space covalency space from space 4 space to space 6.
left parenthesis Si presubscript 14 space equals space 1 straight s squared space 2 straight s squared space 2 straight p to the power of 6 space 3 straight s squared space 3 straight p subscript straight x superscript 1 space 3 straight p subscript straight y superscript 1 right parenthesis.
 
This is because of the absence of d-orbitals in the valence shell of carbon and presence of 3d-orbtials in the valence shell of silicon. Since silicon has vacant 3d- orbitals, it can accept electrons from electron donating species such as F- ion to form complex-ion left parenthesis SiF subscript 6 superscript 2 minus end superscript right parenthesis