Compounds in which transition metals make several anions or neutral molecules are called coordination compounds. Ex: Chlorofyll, haemoglobin, vitamin B-12 etc.
Werner’s theory for coordination compounds: In 1898, a swiss chemist propounded his theory of coordination compounds. The main points of this theory are as follows:
1. Metals show two types of linkages or valences- primary and secondary in coordination compounds.
2. The primary valences are normally ionisable and are satisfied by anions(negative ions).
3. The secondary valences are nonionisable.
4. The ions/groups bound by the secondary linkages to the metal have characteristic spatial arrangements corresponding to different coordination numbers.
Isomerism in coordination compounds: Compounds having same molecular formula but different structures are called and this phenomenon is called isomerism.
Coordination compounds show two types isomerism: 1. Structural isomerism and 2. Stereo isomerism
I.Structural isomerism : Isomerism due the difference in the structures of compounds is called structural isomerism. This isomerism is of four types:
2. Stereo or space isomerism : The isomerism due to the different relative positions of the ligands is known as stereo isomerism. This isomerism is of two types :
I. Geometrical isomerism : The isomerism in which isomers differ in the spatial distribution of atoms or groups about the central atom is known as geometrical isomerism. It is also known as cis-trans isomerism.
Definition: The compounds which are made up of carbon and hydrogen are called hydrocarbons.
Types of hydrocarbons: Hydrocarbons are of mainly three types:
I. Saturated, II. Unsaturated and III. Aromatic
I. Saturated hydrocarbons: Such hydrocarbons which are formed by C-C single bond or C-H single bond are called saturated hydrocarbons.
II. Unsaturated hydrocarbons: Such hydrocarbons which are formed by C-C double or triple or both bonds are called unsaturated hydrocarbons.
Intro: Only a few elements are available in free state. Maximum elements specially metals are found in combined form in earth’s crust. To obtain a metal we have to find such a mineral by mining so that the process to find the metal may be feasible and economical.
The branch of Chemistry which deals with the compounds of carbon is called Organic Chemistry.
Importance of organic chemistry: Without carbon we can’t imagine life on the earth. The number of compounds of only carbon is equal to the number of compounds of all other elements. Many useful products like clothes, rubber, medicines, fuel etc are only due to carbon.
Electrochemistry is the study of production or consumption of electrical energy in a chemical reaction.
Many chemicals are formed by chemical reactions in which electricity is used. For example: sodium hydroxide, chlorine, fluorine etc.
I. Galvanic or voltaic cell:
In chemical kinetics, we study about the rate chemical reactions and their mechanism.
Factors that affect a chemical reaction: 1. Concentration, 2. Temperature, 3. Pressure, 4. Catalyst
Rate of reaction: If we have a reaction as follows:
Average rate of decreasing of the reactant=R/t
Instantaneous rate of increasing the product=P/t
Instantaneous rate of decreasing of the reactant=d[R]/dt
Instantaneous rate of increasing of the product=d[P]/dt
where [R] and [P] are the concentrations of reactant and product respectively.
A solution is a homogeneous mixture of two or more substances. The substance with largest amount is called solvent and other substances with lesser amounts are called solute.
Binary solution : A solution having only two components is called a binary solution.
If you are passionate about the Air Force, you can choose to become an airman as a career. It provides you an opportunity to serve the nation and also to become a part of Indian Defence Services.
For the selection of airmen a board has been formed which is called CASD(Central Airmen Selection Board).It selects airmen through two procedures-
[I]All India Selection Tests & [II]Recruitment Rallies. Advertisements or notices about both procedures are published in Employment News/Rozgar Samachar or different national/regional newspapers. There are two categories of Air Men- Group-”X” And Group-”Y”
The trades in these groups are as follows:
|Automobile Fitter||Education Instructor
[Enrolled In the rank of Sergent(Under/Training)]
|Auto Technician||Adm Assistant|
|Electronics Fitter||Accts Assistant|
|Electrical Fitter||Medical Assistant|
|Mechanical Fitter||Logistics Assistant|
|Mechanical System Fitter||Environmental Support Services Assistant(ESSA)|
|Structure Fitter||Communication Technitian||Ops Assistant|
|Propulsion Fitter||Meteorological Assistant|
|Workshop Fitter(Smith)||Group Training Instructor|
|Workshop Fitter(Mechanical)||Indian Air Force(Police)|
|Weapon Fitter||Indian Air Force(Security)|
(As on date of
|17 – 21 Years||Passed Intermediate / 10+2 / equivalent examination withMathematics, Physics and English, with minimum 50% marks in aggregate and 50% marks in English
Three years Diploma course in Engineering (Mechanical / Electrical / Electronics / Automobile / Computer Science / Instrumentation Technology / Information Technology) from a Government recognised Polytechnic Institure with minimum 50% marks in overall aggregate, and 50% marks in English in Diploma or in Intermediate / Matriculation if English is not a subject in Diploma
| Group ‘X’ :
|20-25 Years||Graduate in Arts, Commerce or Science with B. Ed degree ortwo years teaching experience in a Government recognised School/College, with minimum 50% marks in aggregate in Graduation as well as B. Ed
|20-28 Years||Passed MA English / M Sc in Mathematics, Physics, Computer Science / MCA with B Ed degree or 2 Years teaching experience in a Government recognised School / College|
| Group ‘Y’
( Except Med
|17-21 Years||Passed Intermediate / 10+2 / equivalent examination in any stream / subject approved by Central / State Education Boards with minimum 50% marks in aggregate and 50% marks in English
Passed two years vocational course affiliated / recognised by CBSE / State Education Boards / Councils duly recognised at par with 10+2 by AIU with minimum 50 % marks in aggregate, and50% marks in English in Vocational Course or in Intermediate / Matriculation if English is not a subject in Vocational Course
| Group ‘Y’ :
|17-21 Years||Passed 10+2 / Intermediate / equivalent exam with Physics, Chemistry, Biology and English with a minimum of 50% marks in aggregate and 50% marks in English|
| Group ‘Y’ :
|17-25 Years||Passed Matriculation / 10th class or equivalent with minimum pass marks from any Government recognised School/Boards and proficient in playing at least one of the following musical instruments:
Trumpet / Bass / Violin / Saxophone / Clarinet / Euphonium / Jazz-Drum / Piccolo / Bass Trombone / Key Board / Guitar / Sarod / Viola / Cello / Contra Bass (String Bass).
The elements in d-block are called transition elements. The d-block is from 3rd group to 12th group.