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  Metals and Non-metals ²

• Metals and Non-metals: There are more than 114 elements present in the periodic table. These elements can be broadly classified into two categories i.e., metals and non-metals. Out of 114 elements, 22 are non-metals.
• Physical properties of metals:

(i) They are usually shiny i.e. have a metallic luster. (ii) Metals have a high density (iii) Metals are ductile i.e. they can be drawn into wires. (iv) Metals are malleable i.e. they can be founded into thin sheets. (v) Metals are good conductors of electricity. (vi) Metals have high melting point and are generally in solid state at room temperature. (vii) Metals are good conductors of heat and sound.

• Uses of metals:

(i) Metals are very important for modern humans it is not possible to imagine our life without them. (ii) more...

  Introduction  

• The pollutants may be inorganic, biological or radiological in nature.

(i) Bio-degradable pollutants are domestic wastes which are rapidly decomposed by micro-organisms. (ii) Non-biodegradable pollutants include chemicals, mercuric salts, lead compounds, pesticides, etc. (iii) Natural pollution is caused by radioactive substances, volcanic eruptions, forests and mines fires floods, etc. (iv) Artificial pollution is caused by industries, thermal plants, automobile, exhausts, sewage, etc.   Environment  

• Environment: The conditions existing around animal or human life.

Atmosphere: The gaseous envelop surrounding the earth. It has been classified into following regions:- (i) Stratosphere: The layer of the earth's atmosphere above the troposphere and below the mesosphere. (ii) Troposphere: The lowest region of the atmosphere extending from earth's surface to the lower boundary of the stratosphere. In this region, human beings along with other organisms live. It contains water vapour and more...

  Introduction  

• Definition

Chemistry is a branch of science which deals with study of matter and various changes it undergoes. It deals with the preparation, properties, reactions and structures of chemical elements and compounds. For convenience the study of chemistry is sub-divided into various branches such as: (i) Inorganic chemistry                 (ii) Organic chemistry                   (iii) Physical chemistry                 (iv) Analytical chemistry              (v) Industrial chemistry

• Valency

During the formation of molecules of compounds, atoms combine in certain fixed proportions. This is because of the fact that different atoms have different combining capacities. The combining capacity of an atom or radical is known as its valency.

• Ions or radicals

In addition to atoms and molecules, a third type of particles occurs in substances. These particles, called ions, or atoms or group of atoms that carry an electrical charge. An more...

  Introduction  

• Chemistry has helped significantly in meeting human needs by providing chemical fertilizers, improved varieties of insecticides and pesticides to increase the yield of crops and fruits. It has given us a large number of lifesaving drugs. Also chemical industries manufacturing polymers, soaps, detergents, glass, ceramics etc.

  Industrially Important Compounds Glass It consists of a mixture of two or more silicates.

• Preparation of glass:
• Common glass (or soft glass): It is used to make bottles, glass wares etc. and is obtained by heating together silica (in the form of sand), sodium carbonate or sodium sulphate and chalk or lime stone (calcium carbonate). Some broken glass and a little coke are usually added. The glass so prepared consists of silicates of sodium and calcium.

\[N{{a}_{2}}C{{O}_{3}}(s)+\underset{\left( silica \right)}{\mathop{Si{{O}_{2}}(s)}}\,\to N{{a}_{2}}Si{{O}_{3}}(s)+C{{O}_{2}}(g)\] \[N{{a}_{2}}S{{O}_{4}}(s)+Si{{O}_{2}}(s)\to N{{a}_{2}}Si{{O}_{3}}(s)+S{{O}_{3}}(g)\] \[CaC{{O}_{3}}(s)+Si{{O}_{2}}(s)\to CaSi{{O}_{3}}(s)+C{{O}_{2}}(g)\]

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General Organic Chemistry  

• Wohler prepared the first organic compound urea while preparing ammonium cyanate.
• Classification of organic compounds:

 

• The existence of two or more chemical compounds with the same molecular formula but having different properties owing to different arrangement of atoms within the molecule is termed as isomerism

   

• Hydrocarbons: All those compounds which contain just carbon and hydrogen are called hydrocarbons.
• Functional group: The atom or group of atoms which determine the properties of a compound is known as functional group. e.g. \[-OH\] (alcohol), -CHO (aldehyde), > C = C < (alkene), \[-C\equiv C-\] (alkyne), etc.
• Homologous Series: A series of compounds in which the same functional group substitute’s hydrogen in a carbon chain more...

  Introduction  

• Biodiversity refers number and types of wide variety of plants and animals present on earth.
• In 1773, Swedish botanist Carolus Linnaeus formulated the system of Binomial Nomenclature in his book 'Species plantarum''. In binomial system, each name is expressed in two parts i.e., generic name and specific name.
• Taxon is the branch of biology that deals with the framing of laws and principles for classifying the organisms on the basis of their characteristics and evolutionary relationships.
• The hierarchial system of classification was introduced by

Kingdom \[\to \] Phylum or Division\[\to \] Class\[\to \] Order\[\to \]Family\[\to \] Genus\[\to \]Species

• Species is defined as "the smallest real basic unit of taxonomy which is reproductively isolated from other group of individuals".
• Genus is a group of closely related species that more...

  Introduction  

• Cell is a basic structural and functional unit of life.
• Robert Hooke in 1665 coined the word 'cell'.
• Anton von Leeuwenhoek first saw and described a live cell.
• Robert Brown later had discovered the nucleus.
• Cell theory was proposed by Schleiden and Schwann in 1855 to explain the concept of the cellular nature of living organism.

 

• Prokcaryotic Cells
• Prokaryotic cells are morphologically most primitive.
• Prokaryotic cells are devoid of membrane bound organelles like plastids, mitochondria and advanced (9+2) flagella.
• Prokaryotic cells are represented by bacteria, cyanobacteria (blue green algae) mycoplasma and PPLO (pleuropneumonia like organisms).

 

• Eukaryotic Cells:

A eukaryotic cell consists of the following components:  

• Cell Wall
• The cell wall is a non-living, semi-rigid, external protective covering of the more...

  Means of Transport  

• Diffusion is a random movement of individual molecules from a region of higher concentration to a region of lower concentration. Diffusion rates are affected by concentration gradient, membrane permeability, temperature and pressure.
• The substance that have a hydrophilic moiety, find it difficult to pass through membrane. The movement of such molecules are facilitate, for which proteins provide site at which such molecule cross membrane. This is called as facilitated diffusion.
• Active transport uses energy to pump molecules against a concentration gradient.

  Plants-Water Relations  

• Water Potential: The potential energy of water is referred to as water potential. It is measured in term of pressure.

\[{{\psi }_{w}}={{\psi }_{s}}+{{\psi }_{p}}\]

• Osmosis: It is the diffusion of water through a semi-permeable membrane. It depends on two factors

(i) Concentration of dissolved more...

  Introduction  

• The food that we consume must be broken down into simpler absorbable forms so that they can be easily absorbed and transported to various parts of our body through blood. This task is accomplished by the digestive system.

 

• Dental formula for adult human

\[\frac{Upper\,\,jaw}{Lower\,\,jaw}=\frac{IC\,PmM}{IC\,PmM}=\frac{2123}{2123}\]  

• Digestion of Food

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