Post on 29-Mar-2021
Lesson #3:Formulas & Names of
Ionic Compounds (Part One)
Naming Ionic Compounds
• When naming most Binary Ionic Compounds, we must follow these IUPAC rules:
1. Name the positive ion first by writing the full name of the metallic element
2. Name the non-metal ion next by dropping the last syllable(s) of the name of the element and adding the suffix “ide”
Figuring Out the Formula
• When writing the correct chemical formula for a Binary Ionic Compound, here are the IUPAC rules to follow:
1. Write the symbol of the metallic element first and the non-metal second
2. Determine the charge that each element will have when it forms an ion and write the element in ion notation
3. Balance the charges to get a combination that has ZERO total charge
4. Write the formulaEventually you should be able to do steps #2 and #3 in your head
Lesson #3:Formulas & Names of
Ionic Compounds (Part Two)
What is the name of the following compounds?
FeCl2FeCl3
Binary Ionic Compound Wrinkle #1
• Some Metals can have more than one different charge when they become ions
• The Common Ion Charge is the most likely possible charge that an element can have when it becomes an ion
• The Alternate Ion Charge (or Other Ion Charge) is the other possible charge that the element can have when it becomes an ion
Example: Consider Copper
292+
1+
Cu14.01
Common Ion Charge-means most of the time Copper will have a charge of +2
Alternate Ion Charge- Copper can also have a charge of +1
What are the possible charges for:Iron (Fe)
Tin (Sn)
Lead (Pb)
Mercury(Hg)
Gold (Au)
The Stock System
• Developed by German Chemist Alfred Stock in the 18th century
• A system used to name Binary Ionic Compounds with multi-valence metal ions
• A Roman Numeral representing the charge of the metal ion is inserted between the name of the metal ion and the name of the non-metal ion
Lesson #3:Formulas & Names of
Ionic Compounds (Part Three)
What?!
Mg3(PO4)2
Binary Ionic Compounds
Wrinkle #2:
Dealing with Polyatomic
Ions
• A Polyatomic Ion is an ion made up of more than one element
• When naming an Ionic Compound that contains a polyatomic ion follow these IUPAC rules:
1. Write the full name of the positive ion first
2. Write the full name of the negative ion second IF it is polyatomic (otherwise use the suffix –ide)
Note: The names and charges of several polyatomic ions are on the back of your periodic table
• When writing a chemical formula for an Ionic Compound that contains a polyatomic ion follow these IUPAC rules:
1. Write the symbol or formula for the positive ion first
2. Write the symbol or formula for the negative ion second