Question

Summarize the difference between the chemistries of C and Si, N and P, and O and S ?

Answer 1

Carbon is first element of group 14 of modern periodic table.It is an important element of nature and essential constituent of the living world.Carbon occurs in free state as well as in combined state.It shows anomalous behavior due to small size,higher electronegativity and absence of d orbitals.Carbon shows tendency to form long chains or catenation .Carbon is found in many allotropic forms.

Silicon the second element of group XIV occurs in earth crust in combined state.Silicon ranks second in abundance among the elements found in earth’s crust.Due to infusible nature of silicon and silicates and inertness towards general reagents,chemistery of silicon is much different from that of carbon atom of the same group. Its properties are very similar to boron of group XIII.Silicon is found in two allotropic forms- crystalline and amorphous.crystalline silicon has similar geometry as of diamond while amorphous silicon is a dark brown powder.

Nitrogen is first element of group 15.It shows anomalous behavior due to small size,high electronegativity , tendency to form multiple bonds and non-availability of vacant d orbitals.Nitrogen is a gas while phosphorus is a solid.Ionisation potential of nitrogen is higher than P.Only N has the tendency to form (p-pπ)multiple bonds with itself or with carbon and oxygen.P forms tetrahedral molecules when in elemental state.N is less reactive and does not react with other elements in normal state.While P is highly reactive.

Oxygen is a gas .It is sparingly soluble in water.In liquid state it has light blue colour.it is appreciably soluble in alkaline pyrogallol.It is less reactive at normal temperature due to high bond energy.At high temperature it gives various chemical reactions.Sulphur is yellow coloured, odourless solid substance which is bad conductor of electricity and weak conductor of heat.It shows allotropy.It is insoluble in water but soluble in CS2.It reacts with oxygen,steam,bases,metals and non metals, halogen,shows reducing property and forms explosive mixture with certain oxidizing agents like potassium nitrate and potassium chlorate.