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