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Chemical Bonds

Chemical Bonds. Chemical Bond. The interaction b/ atoms/ions that results in a decrease in potential energy of the system which hence becomes stable. Electron -dot (Lewis) s ymbols. Valence electrons are shown as dots around the symbols of the atoms .

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Chemical Bonds

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  1. Chemical Bonds

  2. Chemical Bond • The interaction b/ atoms/ions that results in a decrease in potential energy of the system which hence becomes stable.

  3. Electron -dot(Lewis) symbols Valence electrons are shown as dots around the symbols of the atoms. 1 2 13 14 15 16 17 18 H He:      LiBe B  C  N  O : F :Ne :            Na Mg AlSiPS:Cl  :Ar :    

  4. Types of bonds • Ionic • Covalent • Metallic

  5. IONIC BONDThe Electrostatic attraction forces happen b/ metal and nonmetal ions as a results of exchanging electrons.

  6. Ionic Bonds: One Big Greedy Thief Dog!

  7. Properties of ionic compounds -have crystalline structure formed of repeating units). -ions stay together as a result of attraction b/ oppositely charged ions. -The 3D structure of the crytalline is named as :lattice.”

  8. Properties of ionic compounds • Hard, brittle. • Relatively high melting and boiling points • Do not conduct the electricity when solid but do when molten or in aqueous solution (since the electrons are free to move). • Are more soluble in water than other solvents

  9. Ex. • Write • Lewis (electron-dot) formula • Chemical formula of the compound formed b/ Mg and O.

  10. Ex. • Write • Lewis (electron-dot) formula • Chemical formula of the compound formed b/ Al and S.

  11. NAMING IONIC COMPUNDS (P.100) • Name of the metal+ ionic name of the nonmetal Compounds Made with Variable Charged Metals Name of the metal (oxidation state of the metal in Roman numeral) + ionic name of the nonmetal

  12. NAMING IONIC COMPOUNDS • NaBr • FeCl2 • Mg3N2 • Al4C3 • CuO • LiH • K3P • PbO2 • CuS

  13. NAMING IONIC COMPOUNDS • BaCO3 • Zn(NO3)2 • Rb3(PO4) • Fe(OH)3 • AgHCO3 CoI2 • CaSO4 NiCr2O7 • CuOH CrCrO4 • MnO2 KMnO4 • K2C2O4 Sr(ClO4)2

  14. COVALENT BOND:Happens b/ nonmetal atoms as a result of sharing electrons.

  15. Covalent Bonds

  16. Many interactions are present: • The attraction forces b/ the electrons and nucleus • Repulsion forces b/ the electrons • Repulsion forces b/ the nuclei

  17. NONPOLAR COVALENT BOND: The shared electrons are attracted w/ an equal power by both atoms in the bonding. H2, Cl2,Br2,Cl2,O2,N2

  18. Oxygen Atom Oxygen Atom Oxygen Molecule (O2)

  19. H2, Cl2:

  20. POLAR COVALENT BOND: The shared electrons are NOT attracted w/ an equal power by the atoms in the bonding. H2O,HF, HCl,NH3,CH4

  21. The bond gets polar as the difference in the electronegativities of the atoms bonded increases.

  22. HCl:

  23. Bond length Bond energy 154 pm 346 kJ/mol C C 134 pm 602 kJ/mol C C 120 pm 835 kJ/mol C C Bond length:The average distance b/ the nuclei of the atoms when the attraction and repulsion forces b/ the atoms are balanced.

  24. Bond length: C-C > C=C > C≡C Bond energy: C-C < C=C < C≡C

  25. Dublet(duet) Rule:Completion of valence electron number to 2 when atoms make bonds in order to reach the stability of He (H,Li). Octet Rule:Completion ve number to 8 when the atoms make a bond in order to reach the stability of Noble gases. (O,N,F,C,Cl,Br,I,P,S…)

  26. Atoms that are out of duet and octet rules: Be,B

  27. Multiple bonds:

  28. Multiple bonds:

  29. Sigma and Pi bonds • Sigma bonds happen as a results of tip-to-tip overlap of the orbitals of the atoms. • Pi bonds happen as a result of side-to-side overlap of the orbitals of the atoms.

  30. Sigma and Pi bonds 2 atoms • Can only make 1 sigma bond. • Can make more than 1 pi bond. Pi bonds are weaker than sigma bonds!!!

  31. •• •• Cl H H Cl • • + • • •• •• Bond formation A covalent bond is formed as a result of overlap of atomic orbitals. H (1s) and Cl(2p)overlap Notice that each atom has one unpaired electron!!!!!

  32. •• H Cl • • •• Lone pair electrons Bonding electrons Cov. Bond and lone (non-bonding) electrons: LEWIS formula!!!

  33. HCl

  34. WARNING!!!!!!!!!!!! All diatomic molecules have a linear geometry…

  35. VSEPR Theory Valence Shell Electron Pair Repulsion

  36. H H N H

  37. d+ d- H F H F Molekül polarlığı = bağ polarlığı • Polar moleküller dipole moment değerine sahiptirler.(vektörelbüyüklük) • Eğer bu dipoller eşit büyüklükte iseler ve toplamları sıfır ediyorsa, molekül apolar bir moleküldür.

  38. CO2 - Nonpolar H2O - Polar

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