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Learn how atoms combine through ionic and covalent bonding to achieve stable electron configurations. Explore examples, electronegativity, and the difference between ionic and covalent bonds. Dive into the concepts of hydrogen fluoride and its polarity. Homework problems included.
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CHEMISTRY 161 Chapter 9 Chemical Bonding I www.chem.hawaii.edu/Bil301/welcome.html
THE OCTET RULE atoms combine to form compounds in an attempt to obtain a stable noble gas electron configuration ns2np6
IONIC BONDING COVALENT BONDING
COVALENT BONDING F F F F THE OCTET RULE sharing electrons (electron pair) electronic configuration of F is 1s22s22p5
F F F F F F + non-bonding, or lone pair of electrons bonding pair of electrons
H2is the simplest covalent molecule + H H H H + the bond length of H2 is the distance where the total energy of the molecule is minimum
EXAMPLES NH3 HX H2O CH4 single bonds O2 CO2 C2H4 double bonds C2H2 N2 HCN triple bonds transition metal compounds w/ halides quadruple bonds
EXAMPLES NH3 HX H2O CH4 O2 CO2 C2H4 C2H2 N2 HCN
IONIC OR COVALENT electronegativity difference between the two atoms involved in the bond
ELECTRONEGATIVITY Li C N O F Na S Cl K Br Rb I Cs Ba Fr Ra is the tendency of an atom in a bond to attract shared electrons to itself F > O > N, Cl > Br > I, C, S …….. Na, Ba, Ra > K, Rb > Cs, Fr Electronegativity increases energies of the atomic orbital with the unpaired electron
ELECTRONEGATIVITY Li C N O F Na S Cl P K Br Rb I Cs Ba Fr Ra F > O > N, Cl > Br > I, C, S …….. Na, Ba, Ra > K, Rb > Cs, Fr Electronegativity increases Se F is the most electronegative H has an electronegativity about the same a P
IONIC VERSUS COVALENT BONDS bonds are neither completely ionic nor covalent (only in homonuclear molecules)
IONIC VERSUS COVALENT BONDS compounds composed of elements with large difference in ELECTRONEGATIVITY significant ionic character in their bonding B has greater electronegativity A B
IONIC VERSUS COVALENT BONDS B has a greater share A B
H F H F HYDROGEN FLUORIDE Fluorine is more electronegative than hydrogen. + +
H F H F HYDROGEN FLUORIDE Fluorine is more electronegative than hydrogen. + + d+ d– This is a polar covalent bond. The bond has a partly ionic and partly covalent nature.
H2O2 NF3 CO32- NO3- OF2 HCOOH H2CO CH3COOH
SUMMARY IONIC BONDING COVALENT BONDING
Homework Chapter 9 pages 338-346, problem sets