Chapter 15Ionic Bonding and Ionic

Compounds

Electron Configuration in Ionic Bonding Ionic Bonds Bonding in Metals

Electron Configuration in Ionic Bonding

Valence Electrons Electron Configuration for Cations Electron Configuration forAnions

Valence Electrons

The electrons in the highest occupied energy level

The number of valence electrons determines the chemical properties

All elements in a group have the same number of valence electrons

Valence Electrons

The number of valence electrons is related to the group number

Group 1 1 valence electron Group 2 2 valence electrons, … Exception: Helium

Valence Electrons

Only valence electrons are shown in an electron dot diagram.

Electron Configuration for Cations

Octet Rule: In forming compounds, atoms tend to achieve eight electrons or the electron configuration of a noble gas.

Metallic elements lose their valence electrons to obtain the octet Na Na+ + e 2-8-1 2-8

Electron Configuration for Cations

Cation – ion with a positive charge (lose electrons)

Some transition metals due not form octets when they lose electrons and they are exceptions Ag (needs to lose 11 electrons to be Krypton

or gain 7 electrons to be Xenon) Loses only 1 electon

Electron Configuration for Anions

Anion – ion with a negative charge (gains electrons) Cl Cl-

Halide ions – halogens that have gained an electron

Chapter 15.2

Formation of Ionic Compounds Properties of Ionic Compounds

Formation of Ionic Compounds

Ionic Bonds – forces of attraction between cations and anions (electrostatic forces)

NaCl Na lose 1 electron, becoming positively

charged Cl gains 1 electron becoming negatively

charged Opposite charges attract each other

Properties of Ionic Compounds

Room Temperature, most ionic compounds are crystalline structures

NaCl

BaSO4 (Barite)

BeAl2(SiO3)6 (Beryl)

Franklinite

Hematite

Properties of Ionic Compounds

High melting points due to very stable structures due to large attractive forces

When melted, can conduct electricity When aq, can conduct electricity

Chapter 15.3Bonding in Metals

Metallic Bonds and Metallic Properties Crystalline Structures of Metals Alloys

Metallic Bonds

Metals are made up of closely packed cations

Surrounded by mobile valence electrons which drift freely from one part of the metal to another

Metallic Bonds – attraction of free floating valence electrons for positively charged metal ions

Metallic Properties

Good conductors of electricity Ductile – Can be drawn into wires Malleable – can be hammered into shapes

Crystalline Structures of Metals

Metals are also crystals just like ionic compounds are crystals

Body Centered Cubic - Chromium

Face Centered Cubic - Gold

Hexagonal Close Packed – Zinc

Alloys

Mixture of two or more elements in which at least one is a metal

Brass

Copper and Zinc

Sterling Silver

Silver (92.5%) and Copper (7.5%)

Coinage Silver

Silver (90%) and Copper (10%)

Cast Iron

Iron (96%) and Carbon (4%)

Stainless Steel

Iron (80.6%), Chromium(18%), Carbon (.4%) and Nickel (1.0%)

Spring Steel

Iron (98.6%), Chromium(1%), Carbon (.4%)

Surgical Steel

Iron (67%), Chromium(18%), Nickel (12.0%) and Molybdenum (3.0%)

14 K Gold (Yellow)

Gold Copper Silver

White Gold

Gold Nickel Zinc Silver Palladium

Why did my GOLD ring turn my skin Green?

A reaction between copper and your skin causes it to turn green or black.

The lower the “K” number, the less gold and more copper.

Gold Plated – can wear off and the filler metal can react with you skin

Nickel allergies – causes staining, itchiness and red