Some strategies for memorization: QUESTION: Which of the following polyatomic ions is not paired with its correct formula? A. permanganate, MnO4-, B. perchlorate, ClO4- C. persulfate, SO4-, D. perbromate, BrO4- Persulfate is S2O82-. Names and formulas of polyatomic ions are trivial information --- just memorize. Some strategies for memorization: Read the names formulas aloud several times. Make up memory aids; find patterns. Work on drills (reading/writing formulas of compounds). Use it or lose it! SCRIPT: Which of the following polyatomic ions is not paired with its correct formula? Nitrate,… borate… carbonate… or chlorate PAUSE CLICK Names and formulas of polyatomic ions are trivial information. In other words, you just need to memorize them as part of the basic vocabulary of Chemistry. Whether or not your teacher requires you to memorize them, it’s a good idea to just memorize them. CLICK Here are some strategies that you can use for memorization. CLICK Refer to a list of names and formulas. Read the names formulas aloud several times. Hearing and seeing should help you remember better than just seeing. Make up memory aids. Try to find patterns in the names and formulas. Work on drills, such as reading or writing of formulas of compounds, that require you to remember these information. Remember that if you don’t use this information, you’re likely to forget it. CONTINUED ON NEXT SLIDE

S2O82-: persulfate (peroxydisulfate) SO42-: sulfate Memory aid: Oxoanions with names starting with “per” and ending with “ate” ClO4-: perchlorate BrO4-: perbromate IO4-: periodate MnO4-: permanaganate S2O82-: persulfate (peroxydisulfate) SO42-: sulfate Here’s an example of a memory aid to remember oxoanions with names starting “per” HIGHLIGHT And ending in “ate” CLICK The most common ones you’ll encounter are perchlorate Perbromate CLICK periodate And permanganate All of these have four oxygen atoms and a charge of –1. You can try to form a word using the symbols for chlorine, bromine, iodine, and manganese. CALLOUT CLOUD “Cl I M Br = climber?” CLICK Let’s locate these elements in the periodic table. Here are Chlorine, bromine, and iodine CLICK They all belong to column 17 or group 7A. HIGHLIGHT group number And here’s manganese CLICK It belongs to column 7, or group 7B HIGHLIGHT group number The other one that is commonly encountered ion with a name starting in “per”… is persulfate, which is more properly called peroxydisulfate. CLICK Sulfate is SO4 with a –2 charge. You can see that peroxydisulfate has twice as many sulfur atoms and twice as many hydrogen atoms as sulfate, but has the same charge.

Video ID: 1-22-3 © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Narrator: Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08