Knowledge Check….

Which Ion is formed from a metal?

List 3 physical characteristics of ionic bonding

Ionic Bonding

Naming & Writing Formulas

Page 61

Ionic bonding occur(Review)

Cations and anions attract each other because they have opposite charges.

The force of attraction between the positively charged cation and the negatively charged anion creates the ionic bond.

Ionic compounds can also be called salts.

What are Monatomic ions?

One-Atom Ions

See Page 218

What are Polyatomic ions?

An ion made of two or more atoms. The charge is on the entire molecule.

Example:

OH- (hydroxide)

See Page 221

What are Binary Ionic Compounds? These compounds contain only two types of

elements.

Example:

Magnesium Oxide - MgO

What are some properties of Ionic Compounds? Very Strong Bonds High melting and boiling points. Solid at room temperature. Liquid and dissolved salts conduct electric

current. Salts are hard and brittle.

Steps To Identify Ionic Compounds Step One: examine the substance. All ionic substances are

solid at room temperature

Step Two: tap the substance gently. All Ionic substances are hard and brittle

Step Three: Heat a small sample of the substance. Ionic compounds generally have high melting points.

Step Four: If the substance melts use a conductivity apparatus to determine if the substance conducts electricity.

Step Five: dissolve the substance in water and use a conductivity apparatus to determine fi the substance conducts electricity.

Rules For Naming Ionic Compounds1) Cation is the name of the element (if two or

more ions are formed from this element roman numerals are used to indicate charge)

Example: Cu1+ (I)ion Cu2+ (II)

2) Anion is formed for the name of the element, but it ends in –ide

Example: Chlorine becomes Chloride

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Practice Problems

Name the following :

NaCl – sodium chloride

ZnS – zinc sulfide

K2O – potassium oxide

Naming Compounds with Polyatomic Ions

1) Name the cation.

2) Name the anion (treat the entire polyatomic ion as one unit).

Some Common Polyatomic Ions

(pg 221)

Rules for Writing the Formula of an Ionic Compound1) Write the symbols for the metal and the nonmetal.

2) Write the valences as superscripts above each symbol.

3) Drop the + and – signs.

4) Crisscross the valences so they become the subscript for the other element.

5) Reduce subscript whenever possible. Only when both are divisible by a number greater than one.

Practice Problems:

Please turn to page 221 in text book.

The teacher will give further instructions.