**Module 4: PART D:*** BINARY (IONIC) COMPOUNDS*

The element written first
in either the name or the formula is a metal. The element written second
is a nonmetal. **Salts** are metallic and nonmetallic ionic
compounds. **There are no molecules of salts-just macro ionic
lattices.** Name the metallic element. If the metallic
element has more than one ionic state, write a *ROMAN NUMERAL** *after
the element’s mane to indicate which charge state the metallic element is using
to form the compound.

Drop the suffix
off the nonmetal’s name and add ** -ide** which indicates the salt is binary

(exceptions: cyanide & hydroxide which are polyatomic ions).

**No**** prefixes** are used to indicate how many atoms are present in the
formula.

Examples:

NaCl Sodium Chloride (table salt)

Al_{2}O_{3}
Aluminum oxide

Fe_{2}O_{3 }
Iron III oxide (rust)

To write the formula from the name of the salt use the following procedure:

**(a) Write the symbols
(or formulas for radicals) of the ions represented
**For Example:

(a)
**Ca N**

_{}_{}

**(b) Use the periodic chart to write the ion charge of
each element (or polyatomic ion) as superscripts: **

_{ }**Ca**^{+2 N-3}

_{ }**(c )
Find the L.C.M. (Least common multiple) of the positive and negative charge. **

*The LCM
is the smallest number that both charges will decide into evenly. The LCM
is the total electrons transferred.
Therefore, it represents the total positive
charge created by the metallic ions and the total negative charge created
by the nonmetallic ions. *This may be
proved by drawing the dot structure of the compound showing all electrons
transferred*.*

* _{ }*The LCM of

--> **6e ^{-1}-->**

(d *(**d) Divide the LCM by the positive charge, this dividend will represent
the subscript behind the metallic ion in the formula.*

+6 divided by +2 = 3;
therefore half of the formula is: **Ca**_{3}**N _{x}**

**(e) Divide the LCM
by the negative charge, this dividend will represent the number of
nonmetallic ions in the formula.**

-6 divided by -3 = 2; therefore the other half of
the formula is: **Ca**_{3}**N _{2}**

**Example:
Potassium phosphide**

Write Charges:

K** ^{+1 }**P

LCM: 3

_{ }Balance the chemical
formula:

**K**_{3}**P**** **** ****
**

_{ }**In addition to working the sample tests,
you may want to practice on writing the names and formulas for Ionic
Compounds. **

**On
Corwin pages 188-9, questions 13 thru 42 are also good practice. **

You must complete the online homeworks:

**D. Binary Ionic Names:**

http://www.lsua.us/chem1001/nomenclature/BinarySalts/BinaryIonic.html

**D1. Binary Ionic Formulas:**

http://www.fccj.us/Nomenclature/BinaryIonicFormula/BinaryIonicFormula.html