Polarity Ch 6.2b 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. Diatomic means ___________________ Many nonmetal elements are often found as diatomic molecules. Atoms of same element share bonding electrons equally. Balanced 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 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 ______________. Electronegativity = Atoms 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 Shared electrons in a hydrogen chloride molecule spend _______ time near the hydrogen atom than near the chlorine atom. Non-polar covalent Electronegativity difference is 0.5 and _______ 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: ________