Download ii. molecular compounds

Chemistry I
Discovery 4-1
Name
Chemical Names & Formulas
Period
Examine the examples in the tables for each section to help you answer the questions.
I.
IONIC COMPOUNDS
a. Metal-Nonmetal
1. In the chemical formula, is the metal or nonmetal symbol written first?
2. In the chemical name, is the metal or nonmetal written first?
3. What do the subscripts in the chemical formula tell you?
4. What do you think is the rule for naming ionic compounds?
5. Examine CaCl2. Multiply the metal ion charge by the number of metal ions.
Multiply the nonmetal charge by the number of nonmetal ions.
Add the two
values together. What do you notice about the overall charge of the compound?
6. Complete the missing parts of the chart by following the patterns you observed.
Chemical
Formula
NaCl
CaCl2
K2S
Li3N
Al2O3
NaBr
Metal
Nonmetal
(M)Name
(NM)Name
Sodium
Calcium
Potassium
Lithium
Aluminum
Chlorine
Chlorine
Sulfur
Nitrogen
Oxygen
M Ion
Charge
+1
+2
+1
+1
+3
#M
atoms
1
1
2
3
2
NM Ion
Charge
-1
-1
-2
-3
-2
# NM
atoms
1
2
1
1
3
Chemical Name
Sodium chloride
Calcium chloride
Potassium sulfide
Lithium nitride
Aluminum oxide
Li2O
Magnesium oxide
Lithium sulfide
Barium nitride
b. Transition Metal-Nonmetal
Transition metals can have different charges when they form ionic compounds. For
example, copper can be +1 or +2. Iron can be +1, +2, or +3.
7. What is the difference in the chemical name of the compounds below from those
in Part IA?
8. What does the Roman numeral tell you about the transition metal?
9. Complete the missing parts of the chart.
Chemical
Formula
CuCl
CuCl2
FeBr3
Fe2O3
Metal
Name
Copper
Copper
Iron
Nonmetal
Name
Chlorine
Chlorine
Bromine
M Ion
Charge
+1
+2
+3
#M
atoms
1
1
1
NM Ion
Charge
-1
-1
-1
# NM
atoms
1
2
3
Chemical Name
Copper (I) chloride
Copper (II) chloride
Iron (III) bromide
FeS
PbS
Lead (III) oxide
Tin (IV) oxide
Chemistry I
c. Polyatomic Ions
Sometimes ionic compounds are formed with polyatomic ions. These are ions that
are formed by more than one nonmetal atom. For example, CO32- is a polyatomic ion
called carbonate with a –2 charge. Many polyatomic ions are listed on the back of
your periodic table or in your textbook (pp. 130). Most of the polyatomic ions end in
“-ate” or “-ite.” Some exceptions are cyanide (CN-) and hydroxide (OH-). Another
exception is also different because it is a positive ion: ammonium (NH4+).
10. How are the chemical formulas of the ionic compounds below different from
those in Parts IA & IB?
11. When are parentheses used in the chemical formula?
12. Complete the missing parts of the table.
Chemical
Formula
CaCO3
KClO3
Ca(NO3)2
Pb3(PO4)2
KOH
Metal
(M)
Name
Calcium
Potassium
Calcium
Lead
Polyatomic
(PA) Ion
Name
Carbonate
Chlorate
Nitrate
Phosphate
M Ion
Charge
#M
atoms
PA Ion
Charge
# PA
ions
Chemical Name
+2
+1
+2
+2
1
1
1
3
-2
-1
-1
-3
1
1
2
2
Calcium carbonate
Potassium chlorate
Calcium nitrate
Lead (II) phosphate
Na2CO3
Mg(NO2)2
Copper (II) sulfate
Lithium carbonate
Calcium phosphate
II.
MOLECULAR COMPOUNDS
d. Nonmetal-Nonmetal
In ionic compounds, we used subscripts to help balance the charges between the
cations and anions. In molecular compounds, we do not have to worry about
balancing charges because the atoms are sharing electrons.
13. Compare the chemical names for CO and CO2. How are they different?
14. How are the numbers of atoms indicated in the chemical name for molecular
compounds?
15. Complete the missing parts in the table.
Chemical
Formula
CO
CO2
PCl5
Nonmetal
#1
Carbon
Carbon
Phosphorus
N2O4
SiCl4
Nitrogen
NM #2
Prefix
Oxygen
Oxygen
Chlorine
# NM1
atoms
1
1
1
Prefix
Chemical Name
Mono
Mono
Mono
#NM2
atoms
1
2
5
Mono
Di
Penta
Di
4
Tetra
Carbon monoxide
Carbon dioxide
Phosphorus
pentachloride
Dinitrogen tetroxide
Oxygen
2
S2O6
Sulfur trioxide
Dinitrogen
tetrasulfide