1. No category

How to Draw a Covalent Lewis
Dot Structure
1. Count Valence e2. Write elements down (closest to carbon
in middle)
3. Draw single bonds
4. Fill outside electrons
5. Fill inside electrons
6. Draw double or triple bonds if needed.
Writing Formulas of Ionic Compounds
chemical formula: has neutral charge;
shows types of atoms
and how many of each
To write an ionic compound’s formula, we need:
1. the two types of ions (i.e., “pink” and “blue”)
2. the charge on each ion
Na1+
and
F1–
NaF
Ba2+
and
O2–
BaO
Na1+
and
O2–
Na2O
Ba2+
and
F1–
BaF2
charge on cation / anion
criss-cross rule:
“becomes” subscript of anion / cation
** Warning: Reduce to lowest terms.
Al3+ and O2–
Ba2+ and S2–
In3+ and Br1–
Al 2 O 3
Ba 2S 2
In 1 Br 3
Al2O3
BaS
InBr3
Writing Formulas w/Polyatomic Ions
Parentheses are required only when you need more
than one “bunch” of a particular polyatomic ion.
and
SO42–
BaSO4
Mg2+ and
NO21–
Mg(NO2)2
NH41+ and
ClO31–
NH4ClO3
Sn4+
and
SO42–
Sn(SO4)2
Fe3+
and
Cr2O72–
Fe2(Cr2O7)3
N3–
(NH4)3N
Ba2+
NH41+ and
Try these on your own paper!
1. cadmium sulfide
11. strontium sulfide
2. zinc iodide
12. lithium oxide
3. iron ( III ) oxide
13. tin ( II ) iodide
4. lead ( II ) chloride
14. Mercury (II) bromide
5. magnesium nitride
15. aluminum fluoride
6. Iron (II) fluoride
16. cesium phosphide
7. Copper (II) bromide
17. silver bromide
8. silver nitride
18. iron ( III ) nitride
9. lead ( IV ) oxide
19. Copper (I) oxide
10. potassium chloride
20. zinc sulfide
Write the Name of each
Compound
1. CuCl2
2. Li3P
3. FeO
4. BaI2
5. Na3N
6. CsBr
7. SnS
8. Ca3N2
9. HgI
10.PbO
11.PbBr2
12.HgS
13.CaF2
14.CuO
15.Cu3P
16.KCl
17.SnS2
18.Cd3N2
19.ZnF2
20.Cs2O
Ionic Compounds (cation/anion combos)
Single-Charge Cations with Elemental Anions
i.e., “pulled off the
Table” anions
The single-charge cations are:
groups 1, 2, 13, and Ag1+, Cd2+, and Zn2+
Na
A. To name, given
the formula:
Ba
1. Use name of cation.
2. Use name of anion (it has the ending “ide”).
NaF
sodium fluoride
BaO
barium oxide
Na2O
sodium oxide
BaF2
barium fluoride
Zn
Ca
Ag
B. To write formula,
given the name:
1. Write symbols for the two types of ions.
2. Balance charges to write formula.
silver sulfide
Ag1+
S2–
Ag2S
zinc phosphide
Zn2+
P3–
Zn3P2
calcium iodide
Ca2+ I1–
CaI2
Multiple-Charge Cations with Elemental Anions
i.e., “pulled off the
Table” anions
The multiple-charge cations are:
Pb, Sn, and the transition elements
(but – of course! – not Ag, Cd, or Zn)
A. To name, given the formula:
Fe
Cu
1. Figure out charge on
cation.
2. Write name of cation.
3. Write Roman numerals
in ( ) to show cation’s charge.
4. Write name of anion.
Stock System
of nomenclature
FeO
2+oxide
?
iron
Fe
O2–
Fe2O3
?
3+oxide
iron
Fe
Fe?3+ O2– O2–O2– iron (III) oxide
CuBr
? Brbromide
1–
copper
Cu1+
copper (I) bromide
CuBr2
1– Br1–
copper
Cu?2+ Brbromide
copper (II) bromide
iron (II) oxide
B. To find the formula, given the name:
1. Write symbols for the two types of ions.
2. Balance charges to write formula.
Co
Sn
cobalt (III) chloride Co3+ Cl1–
CoCl3
tin (IV) oxide
Sn4+ O2–
SnO2
tin (II) oxide
Sn2+ O2–
SnO
Common Polyatomic Ions
ammonium - NH4+
bicarbonate - HCO3chlorate - ClO3cyanide - CNhydroxide - OHnitrate - NO3nitrite - NO2permanganate - MnO4carbonate - CO32-
chromate - CrO42peroxide - O22sulfate - SO42sulfite - SO32phosphate - PO43-
Compounds Containing Polyatomic Ions
Insert name of ion
where it should go
in the compound’s
name.
Write formulas:
iron (III) nitrite
Fe3+ NO31–
Fe(NO3)3
ammonium phosphide
NH41+ P3–
(NH4)3P
ammonium chlorate
NH41+ ClO31– NH4ClO3
zinc phosphate
Zn2+ PO43–
Zn3(PO4)2
lead (II) permanganate Pb2+ MnO41– Pb(MnO4)2
Write names:
(NH4)2S2O3
ammonium thiosulfate
AgBrO3
silver bromate
(NH4)3N
ammonium nitride
CrO42–
? CrO 2–
uranium (VI) chromate
U(CrO4)3 U6+
4
CrO42–
? SO 2–
Cr2(SO3)3 Cr3+
chromium (III) sulfite
3
Cr?3+SO32– SO32–
Covalent Compounds
-- contain two types of
nonmetals
** Key:
FORGET CHARGES!
Use Greek prefixes to indicate how
What to do:
many atoms of each element, but
don’t use “mono” on first element.
1 – mono
2 – di
3 – tri
6 – hexa
7 – hepta
8 – octa
4 – tetra
5 – penta
9 – nona
10 – dec
EXAMPLES:
carbon dioxide
CO2
CO
carbon monoxide
dinitrogen trioxide
N2O3
N2O5
dinitrogen pentoxide
carbon tetrachloride
CCl4
NI3
nitrogen triiodide