I. INTRAMOLECULAR FORCES II. INTERMOLECULAR FORCES Bonding

Chemical Bond A force that holds groups of 2 or more atoms together to make them function as a unit

Why? Atoms form bonds to obtain a “noble gas configuration” Octet Rule- Atoms need to have 8 valence electrons

Types of Bonds Ionic: results from transfer of electrons Covalent: results from sharing of electrons

Ionic Bonds Force of attraction between closely packed opposite ions Atoms that lose electrons easily (metals) Atoms that gain electrons easily (nonmetals) Electrons are transferred from metal to nonmetal Oppositely charged ions form and they attract each other.

Ionic Compounds The ions combine in quantities that provide the stable octet for each element involved They are electrically neutral, so the charges must balance out to zero, as we learned in our formula writing topic.

Properties of Ionic Compounds Hard Poor electrical conductors (solids) Good electrical conductors (in molten and solution) High melting and boiling points Dissolve in water Form crystalline solids

Covalent In covalent bonding electrons are SHARED by the nuclei of each of the atoms present WHY? m/watch?v=1wpDicW_ MQQ m/watch?v=1wpDicW_ MQQ

Characteristics of Covalent Compounds Soft Poor conductors of electricity Poor heat conductors Low melting point High vapor pressures

Lewis Structures for Covalent

Covalent bonding: two types Nonpolar Results from EQUAL sharing Electronegativity difference 0 Polar Results from UNEQUAL sharing Note electronegativity difference between 0 and 1.7

Using Electronegativity to determine bond polarity H-H H-S H-Cl H-O H-F

Choose the More Polar Bond A) H-P or H-C B) O-F or O-I C) N-O or S-O D) N-H or Si-H

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