CHE 106 Lecture Notes - Lecture 5: Ionic Compound, Chemical Formula, Formula Unit

• School: Syracuse University
• Department: Chemistry
• Course: CHE 106
• Professor: J.French

Document Summary

* if we know the molecular formula we know the empirical formula, the opposite is not true* The basic method for determining the order in which elements are listed in a molecular formula is covered by two rules: The number of carbon atoms is listed first, the number of hydrogen atoms listed second, the number of all other elements are then listed in alphabetical order. If there is no carbon in the molecule, then just list all the elements alphabetically (even hydrogen). Molecular compounds are composed of elements covalently bonded together (organic/inorganic) Ionic compounds are ions held together by ionic bonds. An ionic compound is formed from both a cation and an anion. The formula of an ionic compound is written by giving the smallest possible whole-number ratio of different ions in the substance. The formula unit of the substance is the group of atoms or ions explicitly symbolized by its formula. Most ionic compounds contain metal and nonmetal atoms.