UNIT 6 - CHEMICAL BONDING
INTRODUCTION TO CHEMICAL
BONDING
I. Types of Chemical Bonding
A. ____________________: mutual electrical
attraction between the nuclei and valence e- of different atoms
that binds the atoms together
B. Why do atoms bond together?
1. Atoms by themselves have
______ potential energy
2. Want to have ______ P.E.
(this is what happens in nature)
3. Atoms are
____________________ alone than combined with other atoms
C. Electrons are ____________________ during bonding
D. Types of chemical bonding
1.
____________________: results from attraction between large numbers of cations and anions
a.
____________________: positive ion; atom that
has lost e-
b.
____________________: negative ion; atom that
has gained e-
2. ____________________:
results from sharing of e- pairs between two atoms
E. Determining Ionic or Covalent
Bond (Official Way)
1. Remember
____________________? (how much an atom wants to gain
an e-)
2. Difference in EN tells
whether bond is ionic or covalent
a. EN
difference ____________________ (50% or less ionic character) = COVALENT
1. _______________COVALENT: EN difference ______ to ______ (5 - 50% ionic character)
2. _______________ COVALENT: EN difference ______ to ______ (< 5% ionic character)
b. EN
difference greater than ______ (> than 50% ionic character) = IONIC
F. Determining Ionic or Covalent
Bond (Easy Way)
1.
____________________: metal & nonmetal in formula
2. ____________________: 2 or
more nonmetals
a.
____________________: 2 different nonmetals
b.
____________________: 2 of the same nonmetal
COVALENT BONDING AND
MOLECULAR COMPOUNDS
I. Molecules & Molecular Formulas
A. ____________________: neutral group of atoms
held together by covalent bonds -- (ex. one H2O)
B. _________________Molecule: molecule that
contains only two atoms (of the same element)
-->
there are only 7 of them; they are
II. Formation of a Covalent Bond
A. 2 separate atoms far enough away
____________________________________________ on each other
B. As they move ______________, the _______________ (+
chrg.) attracts the ______________ from the
other atom & vice versa
(________________ P.E.)
C. When atoms get too close, the + chrgs.
in nucleus repel each other; + chrgs. from other nucleus & e-
repel each other also
(increase in P.E.)
III. Characteristics of the Covalent Bond
A. ____________________: distance between 2
bonded atoms at their minimum P.E.
1. In other words, avg.
distance between 2 bonded atoms
2. Measured in _______________
(pm) = 1 x 10- m
B. Amt. of energy released when a bond is formed is
______________ to the difference in P.E. from separate
atoms to the minimum P.E.
C. Same amt. of energy must be added to
____________________
D. ____________________: energy required to break a
chemical bond & form isolated atoms
1. measured
in _______________
2. kJ
= _________ J (J = Joule, measure of energy)