Ch.3 - Chemical ReactionsWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds
Jules Bruno

Polyatomic ions are tightly bound groups composed of multiple elements that possess an overall charge. The positively charged ions are called cations, while the negatively charged ions are called anions. 

The charts below show some of the most common polyatomic ions grouped by their respective charges. Unfortunately when it comes to learning them all you will have to sit down and memorize. 


The one major +1 charge polyatomic ion is the ammonium ion. 

NH4-Ion-AmmoniumAmmonium Ion

The +2 charge cation is the mercury (I) ion, which is composed of two mercury ions that are bonded together to form a dimer.  

Mercury-I-Ion-Hg2+-cationMercury (I) Ion

There are many - 1 charge anions and these are the most commonly recognized. 

-1 Charge Polyatomic Anions-1 Charge Polyatomic Anions

Polyatomic ions containing halogens are referred to as oxyhalogens or halogen oxyanions. 

Halogen OxyanionsHalogen Oxyanions

The most common – 2 charge polyatomic ions are: 

-2 Charge Polyatomic Anions-2 Charge Polyatomic Anions

The most common – 3 charge polyatomic ions are: 

-3 Charge Polyatomic Anions-3 Charge Polyatomic Anions

Memorizing these polyatomic ions will be essential later on when dealing with naming binary molecular compounds, naming ionic compounds, and naming oxyacids. In addition our review on the various charges will be further discussed when calculating oxidation states and oxidation numbers.


Jules Bruno

Jules felt a void in his life after his English degree from Duke, so he started tutoring in 2007 and got a B.S. in Chemistry from FIU. He’s exceptionally skilled at making concepts dead simple and helping students in covalent bonds of knowledge.