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Periodic table

Periodic table. 0. IA. post- transition metals. IIA. VA. IIIA. IVA. VIIA. VIA. transition metals. IB. IIB. VB. VIIIB. IIIB. VIB. IVB. VIIB. repulsive Coulomb interaction between ions. repulsive Coulomb interaction between electrons. attractive Coulomb interaction

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Periodic table

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  1. Periodic table 0 IA post- transition metals IIA VA IIIA IVA VIIA VIA transition metals IB IIB VB VIIIB IIIB VIB IVB VIIB

  2. repulsive Coulomb interaction between ions repulsive Coulomb interaction between electrons attractive Coulomb interaction between ions and electrons kinetic energy of electrons Bonding in Solids e e

  3. e e m1 m2 Molecular (van der Waals) bond Crystals of “inert” gases of group 0: Ar, Kr, Xe, Rn R Van-der Waals, London or fluctuating dipole interaction

  4. atom1 atom2 electron charge distribution -1/4 Molecular (van der Waals) bond

  5. cohesive energy Cl- Na+ + 7.9eV + IONIC bond Crystals:NaCl, CsCl, CaCl2 Cl Na Energy balance

  6. R Madelungconstant IONIC bond: Madelung constant

  7. NaCl~ 1.75 CsCl~1.76 ZnS (cubic)~1.64 Madelungconstant IONIC bond: Madelung constant

  8. 3D 2D Covalent bond Crystals:C, Si, Ge, H Covalent bond is formed by two electrons, one from each atom, localised in the region between the atoms (spins of electrons are anti-parallel ) Example: Carbon 1S2 2S2 2p2 C C Diamond: tetrahedron, cohesive energy 7.3eV

  9. H4 C H3 1S 1S Energy H atom H atom H1 H2 H2 molecule Covalent bond Hydrogen molecule Methane molecule

  10. Covalent bond Atoms in group III, IV,V,&VI tend to form covalent bond Filling factor F.C.C :0.74 T. :0.34

  11. e- Attract Attract Repel Repel Na+ Na+ Attract Attract e- Metallic bond Atoms in group IA-IIB let electrons to roam in a crystal. Free electrons glue the crystal Additional binding due to interaction of partially filled d – electron shells takes place in transitional metals: IIIB - VIIIB

  12. H H H F- N C H N O H H+ C C C C C N C H F- N N H C sugar N C C N H sugar The Hydrogen bond Hydrogen bond is formed between the most electronegative atoms: F,O and N. Bonding energyis ~0.1ev Bonding in DNA molecule adenine thymine

  13. Bonding in Solids

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