Ionic Bonds

Chemistry

Mrs. Coyle

Part A:

Ions Lewis Dot Structure Stable Octet (or Duet)

The Periodic Table and Atomic Radius

Valence Electrons

Valence electrons are the electrons in the highest occupied energy level of the atom.

Valence electrons are the only electrons generally involved in bond formation.

Electron Configuration of Sodium

1s2 2s2 2p6 3s1

Which is the valence electron for Na?

Answer: 1s2 2s2 2p6 3s1

Na , 11 e

Na + , 10e

A Positive Ion (Cation):

An atom that has lost one or more electrons. + charge

Electron Dot Structure or Lewis Dot Diagram

A notation showing the valence electrons surrounding the atomic symbol.

Elements within the same group have the same electron-dot structure.

A Negative Ion (Anion)

An atom that has gained one or more electrons.

Negatively (-) charged.

Chlorine Atom Chlorine Ion

When Na, (Z= 11) loses its valence electron, what element does its configuration look like ?

a. Neon

b. Potassium

c. Beryllium

d. Sodium

Check your Neighbor

When Na, (Z= 11) loses its valence electron, what element does its configuration look like ?

a. Neon

b. Potassium

c. Beryllium

d. Sodium

Check your Neighbor

When the valence shell is full, the

atom is stable, less likely to react.

Example: Noble (Inert Gases)

Kr

A Stable Octet

Note

Atoms tend to react in a way that would lead them to have a stable octet.

Part B:

Equations for Formation of Ions and Naming Ions

Ionic Bonds and Ionic Compounds

Equations for the Formation of Cations

H. H+ + e-

Li. Li+ + e-

Mg: Mg2+ + 2e-

Equations for the Formation of Anions

. ..

: F : + e- : F - :

.. ..

Naming cations (+).

Use the name of the metal.

Example: Na+

Sodium ion.

Naming Anions(-)

Use the name of the nonmetal with the ending –ide.

Example: F-

Fluoride

Ionic Compounds

Are made up of: a metal and a nonmetal ion. polyatomic ions.

Naming Ionic Compounds, a First Look

Example: NaF

Sodium Fluoride

Example:

Which of the following compounds are ionic?

1. NaCl

2. CO2

3. CO

4. KF

5. KNO3

Some Common Ions

Bonding

Elements that do not have a complete octet, tend to react.

When the elements react bonds are formed.

Types of Bonds

Ionic Metallic Covalent

Ionic Bonds

Bonds that are formed by transfer of electrons from one element to the other.

Each element (now an ion) will have a complete octet after the transfer of electrons.

The Ionic Bond

• The electrical force of attraction between oppositely charged ions.

Na+ F−

Example: Formation of Lithium Fluoride

. ..

Li. + : F : Li+ : F - :

.. ..

Is an Ionic Compound Electrically Neutral or Charged?

Movie Clip

http://www.youtube.com/watch?v=Kj3o0XvhVqQ&NR=1

Chemical Formula

A representation of the kinds and number of atoms in a substance.

Formula Unit

A chemical formula that shows the lowest whole number ratio of the atoms (ions) in an ionic compound.

Example: KCl, Mg Cl2

The formula unit is used because ionic compounds have a lattice arrangement of ions. Ex: NaCl

Which ball represents the Na?