Metals and Non-metals

Metal   In chemistry, a metal is an element that readily forms positive ions (cations) and has metallic bonds. Metals are sometimes described as a lattice of positive ions surrounded by a cloud of delocalized electrons. The metals are one of the three groups of elements as distinguished by their ionization and bonding properties, along … Read more

Carbon and its compounds

Get Complete Prelims PDF Checkout Added to cart Carbon is the common element found in all known form of life. Structure of all living organism contains carbon. Carbon present in living organism even after death. Coal, petroleum and its products are compounds of carbon. Carbon is an element and a non-metal. Symbol of Carbon = … Read more

Structure of atom

Atomic Structure In 1897 J.J. Thomson discovered electron as a constituent of atom. He determined that an electron had a negative charge and had very little mass as compared to that of the atom. Since an atom was found to be electrically neutral it was inferred that some source of positive charge must be present … Read more

Chemical Reaction

The rate of a chemical reaction can be defined as the amount of the reaction which occurs in unit time. The rate of a reaction is measured by choosing certain properties of the reaction which will indicate how far the reaction has gone, and whose magnitude can be observed with time without disturbing the reaction. … Read more

Acids, Bases and Salts.

Acid An acid is a substance which forms H+ ions as the only positive ion in aqueous solution. Examples:- Hydrochloric acid dissolved in water forms H+ and Cl– ions HCl —> H+ + Cl–   Sulphuric acid dissolved in water forms H+ and SO42- ions H2SO4 —>2H+ + SO42-   Nitric acid forms H+ and NO3– ions when dissolved in water HNO3 —> H+ + NO3–   … Read more

Fundamental unit of life-Cell

  Objects having characteristics of cellular organization, growth, reproduction, ability to sense environment and give response are living organisms. There are some important features of living organisms: It should grow, which means its structure changes as time goes by in an advantageous manner. It should show adaptation to the environment. It should maintain some balanced … Read more

Metabolism

Metabolism  is the set of life-sustaining chemical transformations within the cells of organisms. The three main purposes of metabolism are the conversion of food/fuel to energy to run cellular processes, the conversion of food/fuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates, and the elimination of nitrogenous wastes. These enzyme-catalyzed reactions allow … Read more

Reproduction

Reproductive systems The reproductive system in both males and females consists of structures that produce reproductive cells, or gametes, and secrete sex hormones. A gamete is a haploid cell that combines with another haploid gamete during fertilization. Sex hormones are chemical messengers that control sexual development and reproduction. The male reproductive system consists of structures … Read more

Heredity and Evolution

Evolution, simply put, is descent with modification. This definition encompasses small-scale evolution (changes in gene frequency in a population from one generation to the next) and large-scale evolution (the descent of different species from a common ancestor over many generations). Evolution helps us to understand the history of life. Evolution is not simply a matter … Read more

Gravitation

Newton’s law of universal gravitation states that a particle attracts every other particle in the universe using a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers. Gravitation Gravitation is the force by which every mass or particle of matter, including … Read more

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