before next class · complete chapter 9 quiz due wednesday may 30th · start chapter 8 homework due wednesday june 6th
chapter 8 concepts of chemical bonding 2
chemical bonds 3 basic types of bonds metallic · metal atoms bonded to several other atoms · refers to metal nuclei floating in a sea of electrons ionic · electrostatic attraction between ions e.g nacl · transfer of valence electron covalent · sharing of electrons between atoms e.g cl2 3
energetics of ionic bonding na first ionization energy 495 kj/mol to remove electrons cl electron affinity -349 kj/mol to give electrons to chlorine why is the reaction of sodium metal and chlorine gas to form sodium chloride is so violently exothermic 2na s cl2 g 2nacl
lattice energy · lattice energy the energy required to a mole of a solid ionic compound into its gaseous ions · the energy associated with electrostatic interactions is governed by coulomb s law q 1q 2 eel d 5
energetics of ionic bonding born-haber cycle · diagrams energy changes in the formation of a ionic compound · used to find lattice energies 6
octet rule · octet rule atoms tend to have eight electrons in valence shell · atoms or ions tend to stop losing or gaining electrons once they attain a noble gas configuration · electron configuration of ions can predict stable ion formation fulfill the octet rule · na [ne]3s1 · na [ne or [he]2s22p6 [ne eight electrons in its valence shell.
group problem 1 does the lattice energy of an ionic solid increase or decrease i as the charges of the ions increase increases ii as the sizes of ions increase decreases 2 using the periodic table arrange the following substances according to their estimated lattice energies listing them from lowest lattice energy to the highest licl nabr rbbr mgo rbbr nabr licl mgo