1. Polarity Ch 6.2b

2. Covalent Bonding  When two nonmetals meet - one atom is NOT strong enough to take electrons from the other!  So they must share them  Covalent Bond!  Covalent bond - is a chemical bond in which two atoms ___________ one or more pairs of valence electrons.

3.  Diatomic means “___________________”  Many nonmetal elements are often found as diatomic molecules.  Atoms of same element share bonding electrons equally.  Balanced

4. Unequal Sharing of Electrons  Diatomic compounds share electrons ____________.  Equal forces pulling on the shared electrons  What happens when atoms do __________ share electrons equally?  Unequal forces pulling on the shared electrons

5. Polar Covalent Bond :  Electrons not transferred from one atom to another, but…  Atom with __________ attraction for electrons has a partial negative charge  Other atom has a partial _________ charge.  Types of atoms determine whether a molecule is _______ or ______________.

6.  Electronegativity = Atom’s attraction for electrons  Bigger value  ___________ attraction  Electronegativity trends (attraction for electrons):  Right side of periodic table: ________  Exception for noble gases (Group #8A) - none  Left side of periodic table: low  Top of a group: ____________  Bottom of a group: lower

9.  Shared electrons in a hydrogen chloride molecule spend _______ time near the hydrogen atom than near the chlorine atom.

10.  Non-polar covalent  Electronegativity difference is <_______  Polar covalent  Electronegativity difference is >0.5 and <__________  Ionic bond  Electronegativity difference is >_______

11.  Boron and Hydrogen  Electronegativities: B = 2.0 H = 2.1  Difference: ______   Potassium and Iodine:  Electronegativities: K = 0.8 I = 2.7  Difference: ________   Sodium and Chlorine  Electronegativities: Na = 0.9 Cl = 3.0  Difference: ________ 