Page 215 - Chemistry eBook

Polyatomic Compounds
If a compound has three or more elements in it, we know that it must include a polyatomic ion.
CaOH includes Ca, O, and H. That means it must contain a polyatomic ion.
Polyatomic ions are listed on Table E.
Reffy: Table E (p. 2)
Selected Polyatomic Ions
Table E
This table shows the polyatomic compound’s: 1. Formula
2. Name
3. Charge
Formula
Name
Formula
Name
H3O+
hydronium
Cr O42–
chromate
Hg22+
mercury(I)
Cr2O72–
dichromate
NH4+
ammonium
MnO4–
permanganate
C2H3O2– } CH3COO–
acetate
NO2–
nitrite
NO3–
nitrate
CN–
cyanide
O22–
peroxide
CO32–
carbonate
OH–
hydroxide
HCO3–
hydrogen carbonate
PO43–
phosphate
C2O42–
oxalate
SCN–
thiocyanate
ClO–
hypochlorite
SO32–
sulfite
ClO2–
chlorite
SO42–
sulfate
ClO3–
chlorate
HSO4–
hydrogen sulfate
ClO4–
perchlorate
S2O32–
thiosulfate
(-) means it has -1 charge, (+) means it has a +1 charge.
Let’s check out the first ion listed. The formula is H3O. The name is hydronium. The charge is +1.
Ions That Form Soluble Compounds
Group 1 ions (Li+, Na+, etc.)
ammonium (NH4+)
– nitrate (NO3 )
acetate (C2H3O2– or CH3COO–)
Exceptions
Ions That Form Insoluble Compounds*
carbonate (CO32–) chromate (CrO42–)
phosphate (PO 3–) 4
2– sulfide (S )
hydroxide (OH–)
Exceptions
when combined with Group 1 ions or ammonium (NH4+)
when combined with Group 1 ions, Ca2+, Mg2+, or ammonium (NH4+)
when combined with Group 1 ions or ammonium (NH4+)
when combined with Group 1 ions or ammonium (NH4+)
when combined with Group 1 2+ 2+ 2+
hydrogen carbonate –
(HCO3 ) chlorate (ClO3–)
– – –
Table F
Solubility Guidelines for Aqueous Solutions
UNIT 6: MATH IN CHEMISTRY © 214
halides(Cl ,Br ,I ) whencombinedwith ions,Ca ,Ba ,Sr ,or