Lec.2 Flashcards
(24 cards)
are forces that hold atoms together within a molecule.
Intramolecular forces
are forces that exist between molecules.
Intermolecular forces
is any force that binds together the atoms making up a molecule or compound
An intramolecular force
Transfer of electrons between anon metal & a metal
Ionic Bonds
Ionic Bonds Observed in formation of
salts, example NaCl
Sharing of electrons between two non metals
Covalent Bond
Covalent Bond Observed in
organic compounds , example CH4
Metallic electrons are generally
delocalized
the result is a large number of free electrons around positive nuclei
Metallic bond
Many physical properties reflect intermolecular forces, like
boiling points, melting points, viscosity, surface
tension, and capillary action.
Types of forces
- Binding Forces
a. Cohesion – similar molecules
b. Adhesion – different molecules - Repulsive Forces – prevent molecules from annihilating each other
3.attractive forces
Van der Waals , Hydrogen bond
attractive forces are necessary for
molecules to cohere
repulsive
forces act to
prevent the molecules from interpenetrating and annihilating each other.
Types of Intermolecular Force
Weakest to strongest forces:
dispersion forces
dipole–dipole forces
hydrogen bonding
ion–dipole forces
The London dispersion force It is a temporary attractive force that results when
the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles
London forces are the attractive forces that cause nonpolar substances to
condense to liquids and to freeze into solids when the temperature is lowered sufficiently.
The tendency of an electron cloud to distort is called its
polarizability
Dipole-Dipole interactions result when
two dipolar molecules interact with each other through space. When this occurs, the partially negative portion of one of the polar molecules is attracted to the partially positive portion of the second polar molecule.
A hydrogen bond is an attraction between
a hydrogen atom attached to a highly electronegative atom and a nearby small electronegative atom in another molecule
An ion-dipole interaction is the result of
an electrostatic interaction between a charged ion and a molecule that has a dipole
Examples of van der Waals forces
include
dispersion forces,
and dipole-dipole interactions.
van der Waals bonds can occur between
nonpolar or polar molecules.
van der Waals bonds are extremely dependent on
the distance of separation between molecules,
and are significant only when the electron clouds of the molecules are just touching.
An ideal gas is defined as
one in which all collisions between atoms or molecules are perfectly elastic and in which there are no intermolecular attractive forces.
