Chapter 4Chapter 4

Part 1 - Ionic Compounds

Electron Review

Valence electrons - electrons in the outer energy level.

Core electrons -those in the energy levels below.

Electron Review

Which type of electron is responsible for bonding? Why?

Electron/Periodic Table Review Atoms in the same column:

–Have the same outer electron configuration.

–Have the same valence electrons.

–Easily found by looking up the group number on the periodic table.

Electron/Periodic Table Review

Group 2A

How many Valence Electrons?

Group 8A

How many Valence Electrons?

Noble Gas Configuration

Q: What’s so special about 8 electrons?

A: STABILITY!

Noble Gas Configuration

All atoms seek to achieve the same stability of a noble gas by gaining, losing, or sharing electrons with another atom.

HOW?

Noble Gas Configuration

THROUGH BONDING!• Ionic bonding

• Covalent bonding

Review Question

Group 1A and 2A are what type of element?

(metal, nonmetal, metalloid)

MetalsMetals lose electrons to attain

noble gas configuration.They make positive ions

called cations.

Electron Dots For Cations

Metals will have few valence electrons

Ca

Electron Dots For Cations Metals will have few valence electrons These will come off

Ca

Electron Dots For Cations Metals will have few valence electrons These will lose electrons Form positive ions

Ca2+

Review Question

Group 5A elements are mostly what type of element?

(metal, nonmetal, metalloid)

Nonmetals

Nonmetals gain electrons to attain noble gas configuration.

They make negative ions called anions

Electron Dots For Anions Nonmetals will have many valence

electrons. They will gain electrons to fill outer shell.

P P3-

Noble Gas Configurations All atoms react to achieve noble gas

configuration. Noble gases have 8 valence

electrons Also called the octet rule.

Ar

Ionic BondingAnions and cations are held

together by opposite charges.These are called ionic

compoundsIonic compounds are also

called salts.

Ionic Bonding The bond is formed through the transfer of electrons.

Electrons are transferred to achieve noble gas configuration by both metal and nonmetal.

Ionic Bonding

Na Cl

Ionic Bonding

Na+ Cl-

Ionic Bonding All the electrons must be accounted for!

Ca P

Ionic Bonding

Ca P

Ionic Bonding

Ca+2 P

Ionic Bonding

Ca+2 P

Ca

Ionic Bonding

Ca+2 P-3

Ca

Ionic Bonding

Ca+2 P-3

Ca P

Ionic Bonding

Ca+2 P-3

Ca+2 P

Ionic Bonding

Ca+2 P-3

Ca+2 P

Ca

Ionic Bonding

Ca+2 P-3

Ca+2 P

Ca

Ionic Bonding

Ca+2 P-3

Ca+2P

-3

Ca+2

Ionic Bonding

Ca3P2

Ionic Compound

Properties of Ionic Compounds Crystalline structure. A regular repeating arrangement of ions

in the solid. Ions are strongly bonded. Structure is rigid. High melting points- because of strong

forces between ions.

Crystalline structure

Do they Conduct? Conducting electricity is allowing charges

to move. In a solid, the ions are locked in place. Ionic solids are insulators. When melted, the ions can move around. Melted ionic compounds conduct. Have to get them to 800ºC. Dissolved in water they conduct –

electrons are free to move.

Ionic solids are brittle

+ - + -+- +-

+ - + -+- +-

Ionic solids are brittle

+ - + -

+- +-+ - + -

+- +-

Strong Repulsion breaks crystal apart.

Metallic Bonds How atoms are held together in a metal

solid. Metals hold onto there valence

electrons very weakly. Think of them as positive ions floating in

a sea of electrons. Electrons are free to move from atom to

atom. Electrons moving = electricity!!!

Sea of Electrons

+ + + ++ + + +

+ + + +

Electrons are free to move through the solid.

Metals conduct electricity.

Metals are:Malleable - Hammered

into shape (bend).

Ductile - drawn into wires.

Malleable

+ + + ++ + + +

+ + + +

Malleable

+ + + +

+ + + ++ + + +

Electrons allow atoms to slide by.