1. Naming Ionic Compounds
9.1
Monatomic Ions
Naming Ionic Compounds
1. Monatomic ions: single atom with a charge a. Due to loss or gain of one or more valence electrons.
b. Cations: lose electrons, positive charge from groups 1A (+), 2A (2+), & 3A (3+)
i. Name is the atomic name
c. Anions: gain electrons, negative charge
i. Charge determined by subtracting from the group A number

2. ii. These Group A elements form anions.>
9.1
Monatomic Ions
ii. These Group A elements form anions.>
iii. Anion names start with the stem of the element name and end in -ide.
Note the positions of the nonmetals and the metalloid, arsenic. These elements form anions. Common transition elements that form more than one ion are also shown. Applying Concepts Do the transition metals form anions or cations?

3. d. Ions of Transition Metals
9.1
Monatomic Ions
d. Ions of Transition Metals
i. charges of the cations determined from the number of electrons lost.
ii. Two methods
The Stock system: Roman numeral placed after the name of the element indicates the numerical value of the charge.
The classical method: the classical name of the element is used to form the root name for the element. (less useful, seldom used)

4. 9.1
Monatomic Ions

5. 2. polyatomic ions: are composed of more than one atom.
9.1
Polyatomic Ions
2. polyatomic ions: are composed of more than one atom.
a. names that end in -ite or –ate are anions.
(copy table page 257>)
These models show the structures of four common polyatomic ions.
These molecular models show the arrangement of atoms in four common polyatomic ions. Interpreting Diagrams How does the ammonium ion differ from the other three?

6. CFU
1. When metals from groups 1A, 2A, and 3A form cations, the charge on the ion is equal to
8 minus the group number.
the group number minus 8.
the period number.
the group number.

7. CFU
2. Which of the following are positively charged polyatomic ions?
(I) ammonium ion
(II) perchlorate ion
(III) ferric ion
I only
II only
III only
I and III

8. CFU
3. If the name of an ion ends in -ite or -ate, the ion is a
polyatomic cation.
polyatomic anion.
transition metal cation.
monatomic anion.

9. Binary Ionic Compounds
9.2
Binary Ionic Compounds
B. Writing Formulas for Binary Ionic Compounds
1. Write the symbol of the cation and then the anion. Add whatever subscripts are needed to balance the charges.
a. Write with least common ratios :3>2:1, 2:4>1:2, 6:4>3:2, …
Examples:

10. Compounds With Polyatomic Ions
9.2
Compounds With Polyatomic Ions
2. Compounds containing polyatomic ions
a. Write the symbol for the cation followed by the formula for the polyatomic ion and balance the charges.
b. Examples, calcium nitrate (Ca2+) and (NO3–)  Ca(NO3)2.

11. CFU
1. The correct name for CrCl3 is
chromium chlorine.
chromium(III) chloride.
monochromium trichloride.
chromium(III) trichloride.

12. CFU
2. What is the correct formula for strontium nitride?
Sr3N2
SrN2
Sr2N3
Sr3N

13. CFU
3. Which one of the following compounds is named correctly?
sodium chlorite, NaClO
potassium nitrate, KNO2
sodium acetate, NaC2H3O2
lithium sulfate, Li2SO3