POLARITY OF MOLECULES
AND MOLECULAR
GEOMETRY
POLARITY OF A MOLECULE
• IT REFERS TO HOW EVENLY THE ELECTRONS ARE
SHARED BETWEEN THE ATOMS THAT MAKE UP THE
MOLECULE.
• ELECTRONS ARE SHARED EVENLY = THE MOLECULE IS
NONPOLAR
• ELECTRONS ARE NOT SHARED EVENLY = THE
MOLECULE IS POLAR
MOLECULAR GEOMETRY
• THE SHAPE OF A MOLECULE DEPENDS ON THE
ARRANGEMENT OF ITS ATOMS, AND THIS
ARRANGEMENT AFFECTS THE DISTRIBUTION OF
ELECTRONS IN THE MOLECULE.
TWO KEY FACTORS THAT DETERMINE
MOLECULAR GEOMETRY:
1. THE NUMBER OF ELECTRON PAIRS AROUND THE
CENTRAL ATOM
2. THE NUMBER OF ATOMS BONDED TO THE CENTRAL
ATOM
BASED ON THESE FACTORS, WE CAN PREDICT THE SHAPE OF A
MOLECULE USING A MODEL CALLED THE VALENCE SHELL
ELECTRON PAIR REPULSION (VSEPR) THEORY.
VALENCE SHELL ELECTRON PAIR
REPULSION
(VSEPR) THEORY
• THE VSEPR THEORY STATES THAT ELECTRON
PAIRS AROUND THE CENTRAL ATOM WILL REPEL
EACH OTHER AND SPREAD OUT AS FAR AS
POSSIBLE, LEADING TO SPECIFIC GEOMETRIC
SHAPES.
• THE SHAPE OF A MOLECULE IS CRUCIAL IN DETERMINING
ITS POLARITY.
• IN A NONPOLAR MOLECULE, THE ELECTRONS ARE SHARED
EVENLY BETWEEN THE ATOMS, AND THE MOLECULE HAS A
SYMMETRICAL SHAPE.
• IN CONTRAST, IN A POLAR MOLECULE, THE ELECTRONS ARE
NOT SHARED EVENLY, AND THE MOLECULE HAS AN
ASYMMETRIC SHAPE.