By John Weide with modifications by Ken Costello
Mar 26, 2015
By John Weide
with modifications by Ken Costello
Compounds are two or more elements that are held together by opposite charge attraction.
Oxygen-8Magnesium-12 8 (+)10 (-)-2 Charge
12 (+)10 (-)+2 Charge
Metal Non-metal
Metals combine with non-metals
Metals loose electrons to non-metals
They then attract because their charges will be opposite.
-3 -2 -1
Most of the negative ions have a set negative charge
+1+2 +3
+1 +2
-3 -2-1
POLYATOMIC IONS (charged building blocks)Polyatomic ions are mostly made of two non-metals.
Ions with -1 chargeperbromate BrO4
-1
bromate BrO3-1
bromite BrO2-1
hypobromite BrO-1
perchlorate ClO4-1
chlorate ClO3-1
chlorite ClO2-1
hypochlorite ClO-1
periodate IO4-1
iodate IO3-1
iodite IO2-1
hypoiodite IO-1
nitrate NO3-1
nitrite NO2-1
hydroxide OH-1
cyanide CN-1
acetateC2H3O2
-1
Permanganate MnO4-1
bicarbonate HCO3-1
Ions with a -2 Chargecarbonate CO3
-2
sulfate SO4-2
sulfite SO3-2
chromate CrO4-2
dichromate Cr2O7-2
oxalate C2O4-2
Ions with a -3 Charge
phosphate PO4-3
phosphite PO3-3
arsenate AsO4-3
Ions with +1 chargeammonium ion
NH4+1
Ions with -1 chargeperbromate BrO4
-1
bromate BrO3-1
bromite BrO2-1
hypobromite BrO-1
perchlorate ClO4-1
chlorate ClO3-1
chlorite ClO2-1
hypochlorite ClO-1
periodate IO4-1
iodate IO3-1
iodite IO2-1
hypoiodite IO-1
-1
These polyatomic ions match the charge of the single element
-2
These polyatomic ions match the charge of the single element
Ions with a -2 Chargesulfate SO4
-2
sulfite SO3-2
Ions with a -3 Chargephosphate PO4
-3
phosphite PO3-3
-3
N
Elements with Fixed Oxidation Numbers
La Hf Ta Re OsCe Ba Tl Pb Bi Po At RnIr Pt Au Hg
Y Zr Nb Mo Tc RuRb Sr In Sn Sb Te I XeRh Pd Ag Cd
Sc Ti V Cr Mn FeK Ca Ga Ge As Se Br KrCo Ni Cu Zn
Al Si P S Cl ArNa Mg
B C O F NeLi Be
H H He
Ac Rf Db Sg Rh HsFr Ra Mt
+1+2 +31A
2A
8A
0-4-3-2-17A
6A5A4A3A
W
Nd Pm Sm Eu Gd TbCe Pr Yb LuDy Ho Er Tm
Np Am Cm BkTh Pa No LrCf Es Fm MdU Pu
Click on element to see its oxidation number(s)
Next Slide
Examples #1- Formulas to Names
CuSO3
copper
I’m a polyatomi
c ion
1. Write the names of the ions
Final Name
sulfite(II)
x
X + (- 2) = 0
X = +2
Cu SO3
= 0
You must know the charge on the sulfite ion is -2
The sum of the positive and negative charges must equal zero
2. Determine the charge of the positive ion
-
2
+2 +2
Next
+2
Examples #2- Formulas to Names
KMnO4
potassium
I’m a polyatomi
c ion
1. Write the names of the ions
Final Name
permanganate
If the positive ion has a fixed charge, you are finished.
Examples #3- Formulas to Names
NH4NO3
ammonium
I’m a polyatomi
c ion
2. Determine the charge of the positive ion
1. Write the names of the ions
Final Name
nitrate
If the positive ion has a fixed charge, you are finished.
Examples #4- Formulas to Names
SnF2
tin
2. Determine the charge of the positive ion
1. Write the names of the ions
Final Name
fluoride(II)
Snx (F-1)2 = 0
X + 2(-1) = 0
X = +2
Examples #5- Formulas to Names
Ba(ClO4)2
barium
I’m a polyatomi
c ion
2. Determine the charge of the positive ion
1. Write the names of the ions
Final Name
perchlorateIf the positive ion has a fixed charge, you are finished.
Examples #6- Formulas to Names
Cu2S
copper
I’m not a polyatomi
c ion
2. Determine the charge of the positive ion
1. Write the names of the ions
Final Name
sulfide(I)
2Cux (S)-2 = 0
2X + (-2) = 0
X = +1
Examples #7- Formulas to Names
Na2Cr2O7
sodium
I’m a polyatomi
c ion
2. Determine the charge of the positive ion
1. Write the names of the ions
Final Name
dichromate(I)
2(Nax)(Cr2O7)-2 = 0
2X + (-2) = 0
X = +1
If the positive ion has a fixed charge, it is not shown
Examples #10- Formulas to Names
LiCN
lithium
I’m a polyatomi
c ion
2. Determine the charge of the positive ion
1. Write the names of the ions
Final Name
cyanideIf the positive ion has a fixed charge, you are finished.
Writing Ionic Formulas• It is easier to write the formula of an
ionic compound from its name than the reverse.
• The oxidation number of the negative ion must be memorized in all cases. Refer to the table of polyatomic ions.
Practice Problems
By now you should have an idea of what is expected when naming covalent binary compounds using prefixes.
In order to master this naming system you need to practice until you feel proficient in naming compounds using prefixes.
Practice Problem #1Fe(NO3)3
Choose the correct name for the compound
1. Iron trinitrate
2. iron(I) nitrate
3. iron(III) nitrite
4. iron(III) nitrate
5. none of the abovenext
problemPolyatomic
IonsPeriodic Chart
Practice Problem #2sodium chlorite
Choose the correct formula for the compound
1. NaCl
2. NaClO
3. NaClO2
4. Na(ClO)2
5. none of the above
next problem
PrefixesPeriodic Chart
POLYATOMIC IONS
Ions with -1 chargeperbromate BrO4
-1
bromate BrO3-1
bromite BrO2-1
hypobromite BrO-1
perchlorate ClO4-1
chlorate ClO3-1
chlorite ClO2-1
hypochlorite ClO-1
periodate IO4-1
iodate IO3-1
iodite IO2-1
hypoiodite IO-1
nitrate NO3-1
nitrite NO2-1
hydroxide OH-1
cyanide CN-1
thiocyanate SCN-1
acetate C2H3O2-1
Permanganate MnO4
-1
bicarbonate HCO3-1
Ions with a -2 Chargecarbonate CO3
-2
phthalate C8H4O4-2
sulfate SO4-2
sulfite SO3-2
chromate CrO4-2
dichromate Cr2O7-2
oxalate C2O4-2
peroxide O2-2
Ions with a -3 Chargephosphate PO4
-3
phosphite PO3-3
arsenate AsO4-3
Ions with +1 chargeammonium ion
NH4+1
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N
Oxidation Numbers (most common)
La Hf Ta Re OsCe Ba Tl Pb Bi Po At RnIr Pt Au Hg
Y Zr Nb Mo Tc RuRb Sr In Sn Sb Te I XeRh Pd Ag Cd
Sc Ti V Cr Mn FeK Ca Ga Ge As Se Br KrCo Ni Cu Zn
Al Si P S Cl ArNa Mg
B C O F NeLi Be
H H He
Ac Rf Db Sg Rh HsFr Ra Mt
+1+2+31A
2A
8A
0-4-3-2-17A
6A5A4A3A
W
Nd Pm Sm Eu Gd TbCe Pr Yb LuDy Ho Er Tm
Np Am Cm BkTh Pa No LrCf Es Fm MdU Pu
Click on element to see its oxidation number(s)
+1 +2 +2 +3 +2 +4
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