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icse chemistry books icse chemistry books 1 atoms and molecules i the concept of atoms having fixed properties in explaining the laws of chemical combination the study about the atoms dalton s atomic theory ii atomic and isotopic masses the atomic mass unit is one of the experimentally determined unit it is equal to 1/12 of the mass of the carbon 12 isotope iii chemical equivalents volumetric calculations in terms of normality c 12.00 should be taken as a standard for expressing atomic masses iv relative molecular mass and mole the following methods may be considered for the determination of relative molecular masses for the gases the molar volume method victor meyer s method experimental details not required 2 atomic structure i electrons protons and neutrons as fundamental particles their charges and masses know more about tamilnadu examination board boards.edurite.com page 1/3

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ii rutherford s nuclear model based on the scattering experiment iii bohr s atomic model 1 postulates of bohr s theory ­ based on planck s quantum theory 2 ;umericals on bohr s atomic radii velocity and energy of orbits derivation not required 3 defects in the bohr s model iv atomic structure wave mechanical model a simple mathematical treatment quantum numbers shape size and orientation of s and p orbitals only hund s rule of maximummultiplicity pauli s exclusion principle aufbau principle electronic configuration of elements in terms of s p d f subshells 3 periodic table i atomic number proton number as the basis for classification of the elements in the periodic table iupac nomenclature for elements with z 100 ii extra nuclear structure as the basis of periodicity some idea of the following ionisation enthalpy electron gain enthalpy atomic radius atomic volume electronegativity etc must be given the periodicity of electronic structure leading to the periodicity of elements e.g the relative ease of ionisation of elements iv variable electrovalency and its causes variable electrovalency reasons for variable electrovalency i.e due to inert electron pair effect by using suitable examples covalent bond i covalent bond e.g formation of ammonia nitrogen ethene ethyne and carbon dioxide resonance read more about higher secondary education board boards.edurite.com page 2/3

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thank you boards.edurite.com

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