Chapter 7 Study Guide

Define monatomic ion

an ion formed from a single atom

Define salt

any ionic compound whose cation comes from a base and it's anion comes from an acid

Define empirical formula

The simplest whole number ratio of atoms of each element present in a compound

Define nomenclature

naming system

Define oxyanions

polyatomic ions that contain oxygen

Define percentage composition

the percentage by mass of each element in a compound

Define formula mass

the sum of the average atomic masses of all the atoms represented in the formula of any molecule, formula unit, or ion

Define binary compound

Ionic compounds that contain only two types of monoatomic ions e.g. NaCl

What is the significance of a chemical formula?

It indicates the types and numbers of atoms or ions present in a formula unit or molecule of a compound.

Explain the relationship between the empirical formula and the molecular formula of a given compound

The empirical formula of a compound gives the simplest ratio of the number of different atoms present, whereas the molecular formula gives the actual number of each different atom present in a molecule. If the formula is simplified then it is an empirical formula.

Explain how empirical formula applies to ionic and molecular compounds

The formula for ionic compounds is always an empirical formula because it shows the smallest, whole-number ratio between the cations and anions. The actual number of ions in a sample of an ionic compound will be very large and will vary from sample to sample. The molecular formula indicates the exact number of atoms in the molecule. The empirical formula expresses the smallest whole number ratio of the atoms in the element.