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  THEORIES OF ACIDS AND BASES. There are three basic theories of acid and bases. Arrhenius Theory Bronsted-Lowry Theory Lewis Theory Arrhenius Theory According to the Arrhenius theory, Acid - Any species that increases the concentration of H+ in aqueous solution. Base - Any species that increases the concentration of OH- in aqueous solution. Limitations of Arrhenius Theory It can only describe acid-base chemistry in aqueous solutions.Can not apply in non aqueous and gas phase reactions. Can not apply for certain compounds to explain their acid-base properties. Bronsted-Lowry Theory According to the Bronsted-Lowry theory, Acid - Any species that is capable of donating a proton (H+). Base - Any species that is capable of accepting a proton (OH-). Lewis Theory According to the Lewis theory, Acid - Any species that is capable of accepting a pair of electrons. Base - Any species that is capable of donating a pair of electrons.
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  DALTON'S ATOMIC MODEL John Dalton was an English scientist and a school teacher. In 1808 he formulated a precise definition of the invisible building blocks of matter that we call 'atoms'. Dalton's atomic theory based on four assumptions. Elements are made out of extremely small,indivisible particles called 'atoms'. All atoms of a given element are identical in mass and size but the atoms of one element are different from the atoms of all other elements. Atoms of one element can not be changed into atoms of a different element by chemical reactions;atoms are neither created nor destroyed in chemical reactions. Compounds are formed by union of two or more atoms of different elements in simple mumerical ratio. He suggested that all matters was made up tiny spheres that were able to rebounce around with perfect elasticity and called them as atoms. Dalton's atomic model is called as the Golf ball model. John Dalton Atomic Model
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PERIODIC TABLE   The periodic table is a tabular display of the chemical elements. Chemical elements are arranged in order of atomic number,usually in rows. So that elements with similar atomic structure ( and hence similar chemical properties ) appear in vertical columns. Periodic table widely used in chemistry,physics and other sciences and is generally seen as an icon of chemistry.
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GREATEST  CHEMISTS  OF  ALL  TIME.  Here's the top ten greatest chemists in history. Joseph Priestley  (1733-1804) Louis Pasteur  (1822-1895) Alfred Nobel  (1833-1896) Dmitri Mendeleev  (1834-1907) Marie Curie  (1867-1934) Alice Ball  (1892-1916) Dorothy Hodgkin  (1910-1994) Rosalind Franklin  (1920-1958) Marie Maynard Daly  (1921-2003) Mario Molina  (1943-2020)
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WHAT  IS CHEMISTRY? simple definitions of chemistry: Chemistry is the branch of science that deals with the properties,composition,strucutre of elements & compounds and how can they change and the energy that is released or absorbed when they change. Chemistry is the study of matter; its composition,properties,transformation from one form to another and the energy that accompanies its transformation. There are five major branches of chemistry: Organic Chemistry Inorganic Chemistry Analytical Chemistry Physical Chemistry Biochemistry   Organic Chemistry Organic Chemistry is the study of the structure,properties,composition,reactions and preperation of carbon containing compounds. Inorganic Chemistry Inorganic Chemistry deals with synthesis and behavior of inorganic and organometalic compounds.This field covers chemical compounds that aren't carbon based. Analytical Chemistry Analytical Chemistry is the science of obtaining,processing and communicating information about the
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