Polarity and Dipoles
Electronegativity is The attractive force on electrons by atoms
- increases when the positive nucleus of atoms can get closer to other electrons
☆ Bond type determination
- metal and a nonmetal form ionic bond
- two nonmetals form covalent bonds
☆ electronegativity differences to show the type of bond
・ ionic bonds have a differential of 1.8 - 4.0
・ covalent bonds have a differential of 0.0 - 1.8
- nonpolar covalent bonds - 0.0 - 0.4
- polar covalent bonds - 0.4-1.8
☆ polar versus nonpolar
-a polar bond means there is enough of a overall difference in electronegativity so that there is a positive and negative side to a covalent bond
-δ+ (Delta positive) means electrons move away from δ- (Delta negative) is the side where electrons move closer to.
・ a nonpolar bond is when the electronegativity difference between both atoms is 0 or close enough to zero that the electrons are shared equally within the bond
・BOTH are covalent bonds
Bond polarity
- determined by electronegativity difference
- between two atoms only
0.0 - 0.4 NPC
0.4 - 1.8 PC
1.8-40 ionic
Molecular polarity
symmetrical - nonpolar
asymmetrical - polar