Chapter 7

Ionic Covalent and Metal Materials

Types of AtomsIonic

Compounds:

Covalent

(Molecular Compounds):

Metallic Solids:

Ions

(Ca+ions

& Anions)

Two or more

nonmetal atoms

2 or more

metals atoms

Electron Dot structures

valence electrons: as dots around the atomic symbols EX. Ne

• Octet Rule - atoms react until contain 8 valence e-

F Ne_

(Fluorine) Ions achieve electron configuration as Noble Gas Neon

Halide Ions

halogen, become negative gaining 1 electron.

F I BrFluorin

e IodineBromine

__

_

Fl0urine, Iodine and Bromine are all halogens - Halide Ions.

+

Ionic Bonds• force binds oppositely charged

ions

Na

ClSodium (Cation) Chlorine

(Anion)

-

Sodium chloride

Sodium

Electrostatic Attraction

B. Two types of compounds

Ionic Ionic CompoundsCompoundsMade from Made from

IOIONSNSatoms w/ positive or negative charges.when an atom has lost or gained electrons.

• Good conductors when dissolved/melted.

ca+ion & anion

Electrically Electrically neuneutraltral

Na Na ++

Cl Cl --NaClNaCl

+Crystalline Solid -

Bond formationIonic Compounds:

Covalent (Molecular):

Metallic Solids:

Transfer of electrons

Sharing of electrons

Free moving valence e-

Bond formation

room temperature crystalline

Hard & Brittle, High Melting pt

solid, liquid or gas. soft & low melting point

Soft to very hard Higher valence # of e- , harder metal.

Electrostatic forces

Very Strong

Weak

Strong

How many Na+

surround Cl-?

Na+

Na+

Na+

Na+Na+

Na+

Na+

Na+Na+

Na+

Na+

Na+Na+

Na+

Na+

Na+

Cl-

Cl-

Cl-

Cl-Cl-

Cl-

Cl-

Cl-Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+Na+

Na+

Na+

Na+Na+

Na+

Na+

Na+Na+

Na+

Na+

Na+

Cl-

Cl-

Cl-

Cl-Cl-

Cl-

Cl-

Cl-Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+Na+

Na+

Na+

Na+Na+

Na+

Na+

Na+Na+

Na+

Na+

Na+

Cl-

Cl-

Cl-

Cl-Cl-

Cl-

Cl-

Cl-Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Compound ArrangementIonic Compound

•Oppositely charged ions close packed layers.

Unit cell

repeating 3D pattern :

Crystal

Even at this point, there was still a Polar Covalent Bond between Sara, Johnny and Bill…

Johnny didn’t like the feeling of competing with Bill but he knew if he really wanted her,

he’d have to fight for her.

Stop in the name of Love, before You break my heart.

Covalent Compound

•nonmetals bonds between molecules are weak

Water molecules

Weak forces

•Low to high mt. pts.

•Ductile: can be

hammered into different shapes

•Malleable:

can be drawn into wires

•Metals:

e- e-

Form a bond

Electron cloud

ConductorsMetallic Solids:

Good conductors of heat

Why?

• Free-moving valence electrons

• Free-moving valence electrons

Why?

in the molten state.

or as electrolytes

Ionic Compounds:

Conductors

Bonds break (melt) or dissociate (dissolve).Ions separate - free to

move around.

Poor conductors

Molecular Compounds:

Don’t form ions

Network Solids• Consist of atoms held together by large network of covalent bonds.• Each atom is covalently bonded in a large chain or network.• There are NO molecules in a network solid, only atoms bonded together.Example: Diamond

• Bonds are very strong.

Network Solid

Hardsfc.mov