Octet Rule - Atoms tend to gain, lose, or share electrons until they are surrounded by eight electrons (4 electron pairs).. Saved by Erika Swegles Daman. C2H5Cl < C2H6 < C2H5OH C2H6 < C2H5Cl C2H5Cl + H3PO3, when the reaction was carried out, the actual yield of C2H5Cl was calculated as 97.3% of the theoretical value. Polar molecules must contain polar bonds due to a difference in electronegativity between the bonded atoms. How is vsepr used to classify molecules? Structural formulas are helpful because they explain the properties and structure of the compound which empirical and molecular formulas cannot always represent. C2H6 < C2H5Cl