Chapter 4, Section 1Ionic Bonds

Thursday, December 3, 2009

Pages 114 -- 120

Objectives

• Explain the differences between an atom and an ion.

• Describe how an ionic bond forms.

• Identify the properties of ionic compounds.

Vocabulary Words

• Ion

• Ionic bond

• Polyatomic ion

• Crystal

Quick Review

• When can electrons transfer?• Valence electrons• Stable element• Reactive element

• Atoms either gain or lose electrons to become more stable.

Ion

• An ion is an atom or group of atoms that has become electrically charged.• When an atom loses an electron (loses

negativity) it becomes a positive ion.• When an atom gains an electron (gains

negativity) it becomes a negative ion.

Ionic Bond

• An ionic bond is the attraction between two oppositely charged ions (like opposite poles of the magnet).

• In this example, the sodium ion is balanced by a chloride ion.

• The formula NaCl shows a 1:1 ratio.

QuickTime™ and a decompressor

are needed to see this picture.

Polyatomic Ions

• Polyatomic Ions are ions made of more than one atom.

• It is a group of atoms that act as one.

QuickTime™ and a decompressor

are needed to see this picture.

Properties of Ionic Compounds

• The characteristic properties of ionic compounds include:• crystal shape• high melting points• electrical conductivity

Homework

• Workbook 4.1 (due 12/8)

• Vocabulary quiz 4.1 (12/8)