Chapter 7-8

 Periodic Chart is organized relative to periodic properties (by families)  Chemical Bonding occurs in order to follow the Octet Rule  Octet Rule states that a point of stability within chemicals occurs with a s 2 p 6 configuration

 Distance between nucleus and outmost electron in a bonded atom

 Energy needed to remove the most loosely held electron from the atom

 Other points of stability occur within chemistry  Full subshells (s 2 p 6 d 10 f 14 )  ½ full subshells (s 1 p 3 d 5 f 7 )

 Distance from the nucleus to the outermost electron in an atom  Cations – smaller than the original atom  Anions – larger than the original atom

 Energy released when an additional electron is acquired by the atom (Desire for additional electron)

 Metal Properties  Nonmetal Properties  Metalloids

 Also follows periodic properties because electrons in the outer energy level are the makers of properties

 Ability of an atom to attract electrons to itself, when involved in bonding  Differences in electronegativity (END) determines bond character  Large difference (END > 1.67) is strongly IONIC  Small difference(END<1.67) is strongly COVALENT

 Chapter 7 #16,18,19,24,32 Chapter 8 #1,2,4,8,10,23,24,38

 Complete transfer of electrons due to large differences in electronegativity (END>1.67)  Metal + Nonmetal  Charged particles held together by electrostatic force of attraction called Lattice Energy ionic bonding example

 Bond Character (mostly due to charged ions)  Intraparticle (within)  Strong bond  High solubility (strong electrolyte)  High conductivity in aqueous solution  Interparticle (between)  Usually solids  High melting point  Crystalline (ionic compound)  Hard

 Sharing of electrons due to small differences in electronegativity (END < 1.67)  Nonmetal + Nonmetal  Held together by sharing of electron to satisfy octet rule covalent bonding example  Pure Covalent Bond (equal sharing of e-)  Polar Covalent Bond (unequal sharing or e-) polar molecule

 Polarity of a covalently bonded particle effects a variety of properties and is an important concept in chemistry  Polarity occurs when there is an ASYMETRICAL CHARGE DISTRIBUTION and a dipole or polar molecule is created

 Bond Character mostly due to sharing of electrons  Intramolecular (within)  Weak bond  Low solubility (remains intact as molecule)  Low conductivity in aqueous solution  Intramolecular (between)  Usually gas, liquid or low melting point solid  Low boiling point  Amorphous (noncrystalline)

 Ex: NH 3, CH 4, O 2

 Delocalized electrons travel among the nuclei  “SEA OF ELECTRONS”  Properties  Very strong bonds  Highly conductive in solid form  High melting point