Additional Questions for Electronegativity
Electronegativities
Using the periodic table as your guide, which element is more electronegative for each pair
given?
The closer the element is to fluorine the more electronegative the element. There is also an
electronegativity chart which will be given for later problems. Locate each element on the
periodic table
Na or Rb
Br or Ca
Ge or O
Polar vs. Nonpolar Covalent Bond
Covalent bonds are sharing of electrons. There are two types of covalent bonds
1 ) Polar Covalent Bond = Unequal sharing of the bonding electrons. The bonding electrons are
fighting for the shared electrons…who is the winner? The most electronegative atom! If a polar
covalent bond is present draw the dipole (points toward the winner) Example: Water
2) Nonpolar Covalent Bond = Equal sharing of the bonding electrons. Example: H2O2N2Cl2
Br2I2F2
Solubility = able to be dissolved
Principle for solubility = Like Dissolves Like
Using the electronegativity value for each element, classifying the bond as polar covalent bond,
nonpolar covalent or ionic. Draw the dipole for any bonds classified as polar covalent. Be sure
to use the absolute value after taking the electronegativity difference.
You will be given the electronegativity values or can look them up. The absolute value (always a
positive value) of the difference is used. Remember these values:
Bond Classification
Electronegativity Difference
Nonpolar covalent
less than 0.5
Polar covalent
0.5 - 1.8
Ionic
greater than 1.8
HH or H2= 2.1-2.1 = 0.0 (nonpolar covalent)
OH = 3.5-2.1 = 1.4 (polar covalent, dipole points toward oxygen)
NaCl = .9-3.0 = 2.1 (ionic)
Classify which bond is more polar HCl or AlH? The bigger the difference the higher the polarity