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 s2p6 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 (s2 p6 d10 f14) ½ full subshells (s1 p3 d5 f7)

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 rulecovalent 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: NH3 , CH4 , O2

Delocalized electrons travel among the nuclei “SEA OF ELECTRONS”

Properties Very strong bonds Highly conductive in solid form High melting point