6.1 Ionic Bonding

Stable Electron Configurations

• When the highest occupied energy level of an atom is filled with electrons, the atom is stable and not likely to react.

• Noble gases have stable configurations with full valence electrons.

• The chemical properties depend on the valence electrons.

• Lewis created a model of showing the valence electrons– Called the Electron dot diagram, or also the Lewis Dot Structure.– Nitrogen, Group 5A

Examples…..

Ionic Bonds

• Elements that do not have complete sets of valence electrons tend to react.

• Some elements achieve stable electron configurations through the transfer of electrons between atoms.

Transfer of Electrons

Formation of Ions

• In a neutral atom the number of protons is equal to the number of electrons.

• When an Ion is formed, the number of electrons is not equal to the protons.– It has an unbalanced charge called an ion.

• The charge is represented by a (+) or a (-) sign.

• The goal is to create stable atoms.

Examples

• Chlorine has 17 electrons normally.• – When it gains an electron it has 18, called an

ION• It now has a charge of 1-.• Written as Cl1-

• Negative Ions take the suffix “ide” in general.• Chlorines Ion is Chloride

• Negatively charged Ions are called ANIONS

• Sodium ions have 11 protons and 10 electrons.

• One more proton than electron means it has a 1+ charge.

• Can be written as Na1+

• An ion with a positive charge is called a CATION

• When a cation and an anion are close together a chemical bond forms.

• The type of chemical bond is an IONIC BOND.

Ionization Energy

• The amount of energy needed for an electron to move to a higher energy level.– Allows e- to overcome attraction of nucleus.– Takes more energy to remove e- from a nonmetal than a metal– Decreases down a group, increases across a period.

Trends in the Periodic Table

Drawing Ionic Compounds

Draw an example of this….. Magnesium Chloride.

• 1. Draw electrons (dots)• 2. Move e- to most stable configuration• 3. Draw arrows to show new location• 4. Write the new charge of the ions formed

• Written as MgCl2