If you are a student of 10th class, then this chapter bears a lot of importance for you. Go through the following questions and answers to perform better in your exams.
What would be the electron dot structure of carbon dioxide which has the formula CO2?
The distribution of electrons in carbon and oxygen is represented as:
Carbon K= 2, L= 4.
Oxygen K = 2, L= 6
Valency of carbon is 4 and that of oxygen is 2, therefore carbon atom shares its four valence electrons with two oxygen atoms. Thus the electron dot structure of CO2 is as:
What would be the electron dot structure of a molecule of Sulphur, which is made up of eight atoms of Sulphur? (Hint – The eight atoms of Sulphur are joined together in the form of a ring.)
Sulphur has atomic no. 16. Its electronic configuration is given by; K= 2, L= 8, M= 6.
Since Sulphur atom is short of two electrons so as to complete its octet. Therefore, each Sulphur atom shares two valance electrons with two neighboring Sulphur atoms and an eight membered ring is formed.
What are the two properties of carbon that lead to the huge number of carbon compounds we see around us?
The two properties of carbon responsible for existence of huge number of carbon compounds are (i) Catenation (ii) Small size and tetra valency of carbon.
(i) Catenation: The property of forming bonds with atoms of the same element is called catenation (self linking property). Carbon shows maximum tendency for catenation in the periodic table. This is because of formation of strong bonds between two adjacent carbon atoms as compared to other atoms. It is due to this strong self linking property of carbon that organic compounds have long chain, branched chains and ring structure of carbon atoms, which is one of the reasons for existence of large number of organic compounds.
(ii) Tetra valency and Small size :- Due to its tetra valency, carbon atoms can form covalent bonds with four other carbon atoms or with a large number of other atoms such as hydrogen, oxygen, nitrogen, sulphur, chlorine and others.
Carbon forms multiple (double and triple) bonds with other carbon atoms as well as with oxygen and Nitrogen. These multiple bond are very strong as compared to single bond and the reason for formation of these multiple bonds is the small size of carbon atom. Thus tetra valency together with small size of carbon is the another reason for existence of large number of organic compounds.
What will be the formula and electron dot structure of Cyclopentane?
In cyclopentane each carbon atom shares its two valence electrons with two neighboring carbon atoms and two valence electrons with two hydrogen atoms.
Formula of Cyclopentane is C5H10
A mixture of oxygen and Ethyne is burnt for welding. Can you tell why a mixture of Ethyne and air is not used?
When a mixture of oxygen and ethyne is burnt, it burns completely producing a blue flame. This blue flame is extremely hot which produces a sufficiently high temperature required to melt metals for welding. But the mixture of ethyne and air is not used for welding purposes because burning of ethyne in air produces a sooty flame due to incomplete combustion, which is not too hot to melt metals for welding.
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