A large number of silicate minerals exist in nature. Some of the important minerals are : feldspar i.e. Albite NaAlSi3O8 , zeolites e.g. chabazite Ca2[(AlO2)4 (SiO2)8.H2O, micas [KAl2(Si3AlO10(OH)2] and asbestos [Mg3(Si2O5)(OH)4]. The basic structural unit in silicate is the SiO44- terahedra. The two important man-made silicates are glass and cement. Silicates are … [Read more...] about Silicates
p-Block Elements
Silicones
Silicones are synthetic organosilicon polymers containing repeated R2SiO units held by Si-O-Si linkages. These compounds have general formula (R2SiO)n where R=methyl or aryl group. Preparation When methyl chloride reacts with silicon in the presence of copper as a catalyst at 570 K , various types of methyl substituted chlorosilanes of formula CH3SiCl3 , … [Read more...] about Silicones
Allotropes Of Carbon
The phenomenon of existence of an element in two or more forms which have different physical properties but identical chemical properties is called allotropy and the different forms are called allotropes. Carbon exists in 2 allotropic forms: 1) Crystalline 2) Amorphous Crystalline form of carbon: 4 allotropes of carbon having well defined crystal structure … [Read more...] about Allotropes Of Carbon
Silicon Dioxide, Silica
Silicon dioxide is known as Silica , SiO2. 95 % of the earth crust is made up of silica and silicates.It occurs in several crystallographic forms , namely , quartz , cristobalite and tridymite.These crystalline forms are interconvertible at suitable temperature. Structure Silicon dioxide is covalent , three- dimensional network solid in which each silicon atom is … [Read more...] about Silicon Dioxide, Silica
Carbon dioxide
Preparation 1) It is prepared by burning carbon, fossil fuels and other organic compounds in excess of air or oxygen. C (s) + O2 (g) -------> CO2 (g) C5H12 (g) + 8 O2 (g) --------> 5 CO2 (g) + 6 H2O (g) 2) In the laboratory , it is prepared by the action of dilute acids on carbonates. CaCO3 + 2 HCl -------> CaCl2 + CO2 + H2O 3) Commercially , CO2 is … [Read more...] about Carbon dioxide
Carbon Monoxide
Preparation 1) It is formed by incomplete combustion of carbon and carbon containing fuels. 2 C + O2 ------> 2 CO This type of incomplete combustion occurs during burning of petrol or diesel in automobile and therefore CO is always present in automobile exhausts.It is also present in volcanic gases and gases coming out of furnaces. 2) In the laboratory , pure … [Read more...] about Carbon Monoxide
Chemical Properties of Carbon Family
Oxidation State (1) Oxidation state of Carbon The general valence shell electronic configuration of elements of group 14 is ns2 np2 where n is the number of outermost principal shell. These elements can attain inert gas configuration either by losing or gaining 4 electrons forming M4+ or M4- ions. The C4+ ion does not exist firstly because it is a highly charged species … [Read more...] about Chemical Properties of Carbon Family
Physical Properties Of Carbon Family
Group 14 include Carbon (C) , Silicon (Si), Germanium(Ge) ,tin(Sn) ,lead(Pb) and ununquadium (uuq) which is radioactive. Occurrence Carbon is the 17th most abundant element by weight in the earth crust. It occurs in the native state in form of coal ,graphite and diamond. In combined state it occurs widely as metal carbonates, hydrocarbons ,carbohydrates and carbon … [Read more...] about Physical Properties Of Carbon Family
Chemical Properties of Boron Family
Oxidation State The elements of group 13 have to two electrons in the s- orbital and one electron in the p-orbital of the valence shell. These elements are expected to show a uniform oxidation state of +3. Boron and aluminium which show an oxidation state of +3 only but gallium, indium and thallium due to inert pair effect show oxidation state of both +1 and +3 . As we … [Read more...] about Chemical Properties of Boron Family
Anomalous Behaviour Of Carbon
Carbon, the first member of group 14 ,shows an anomalous behaviour i.e. differ from rest of the members of its family. The main reason for this difference are : 1) exceptionally small atomic size b) higher electronegativity c)higher ionisation enthalpy d) absence of d orbital in the valence shell The main point of differences are: 1) Carbon in form of … [Read more...] about Anomalous Behaviour Of Carbon