Ionic Bonding Notes-Part 3
There are some metals that can lose ____________________ than just one amount of electrons. Most of these
metals are ____________________ metals, but also some of the metals directly below the stairstep line do this.
Because there is more than one possible positive charge for these metals, a way of naming them is needed to specify
which charge it has.
The new system uses the normal name for the metal and then added a ____________________ numeral in
parentheses to stand for the charge.
Here are the first nine roman numerals:
I=1
II = 2
III = 3
IV = 4
V=5
VI = 6
VII = 7
VIII = 8
IX = 9
Also, several transition metals only have one charge possible, so they don’t need a roman numeral (MEMORIZE):
Cadmium
Cd+2
Silver Ag+
Zinc
Zn+2
When naming an ionic compound with a metal that can have more than one charge, the ____________________
charge will tell you how much positive charge the metal must have. The nonmetal still ends in “______________”.
Examples:
FeO
Fe2O3
Oxygen must have a -2 charge
There is 1 oxygen
The total negative charge is -2
Oxygen must have a -2 charge
There are three oxygens
The total negative charge is -6
The total positive charge must be +2
There is 1 iron
Thus the iron has a +2 charge
(+2 / 1 = +2)
The total positive charge must be +6
There are two irons
Thus each iron has a +3 charge
(+6 / 2 = +3)
Ionic Compounds with Transition Metals
Exercise 7:
1) In the following grids, write in the symbol and charge for the stated transition metal.
2) Criss-cross to form a neutral compound. Use parentheses if necessary.
3) Reduce if possible!
-3
-2
N
S
Br
F
OH
Chromium (III)
Cobalt (III)
Copper (I)
Copper (II)
Gold (III)
Iron (II)
Iron (III)
Manganese (II)
Manganese (IV)
SO4
-2
Naming Ionic Compounds with Transition Metals
When a transition metal is already in an ionic compound, there is no immediate statement of the charge.
However, the charge on the nonmetal (the anion) will never change. So if the total of the negative charges is
added up, the total of the positive charges must be the same. Thus, by a little math, the charge of the transition
metal can be determined, and then the name for the transition metal is known.
Examples:
FeO
Oxygen must have a -2 charge
There is 1 oxygen
The total negative charge is -2
Fe2O3
Oxygen must have a -2 charge
There are three oxygen
The total negative charge is -6
The total positive charge must be +2
There is 1 iron
Thus the iron has a +2 charge
(+2 / 1 = +2)
So
Iron (II) Oxide or
The total positive charge must be +6
There are two irons
Thus each iron has a +3 charge
(+6 / 2 = +3)
So
Iron (III) Oxide
Exercise 8:
For each of the following formulas, write the name of the compound. Don’t forget to change the end to “ide” if
necessary.
11.
13.
15.
17.
19.
CrN ____________________________
Cu3N2 ____________________________
Fe2Se3 ____________________________
HgCl2 ____________________________
MnO2 ____________________________
12. CoI2 ____________________________
14. Au3P ____________________________
16. MnF2 ____________________________
18. MnP ____________________________
20. NiN _____________________________
Writing Ionic Compound Formulas from their Names
When ionic compounds that contain transition metals are named, the names indicate the charge. Then, just like
before:
1) Write the symbols for the metal and the nonmetal or polyatomic ion.
2) Figure out the charge on each.
3) Criss-cross the charges and reduce. Don’t forget to use parentheses if necessary.
Exercise 9:
For each of the following named ionic compounds, write the correct formula. Both classic system and stock
system names will be used.
1.
3.
5.
7.
9.
Chromium (III) Phosphate __________
Cobalt (II) Phosphide
__________
Gold (III) Oxide
__________
Copper (I) Carbonate
__________
Manganese (IV) Silicate __________
2. Nickel (III) Bromide
4. Mercury (II) Phosphide
6. Manganese (II) Selenide
8. Iron (III) Acetate
10. Chromium (II) Iodide
__________
__________
__________
__________
__________