molecule’s atoms. The structural theory that deals with the bond angles is called
the VSEPR theory, whereas the one that describes changes in the orbitals that
contain the valence electrons is called the hybridization theory. (VSEPR
represents Valence Shell Electron Pair Repulsion.)
VSEPR uses as its basis the fact that like charges will orient themselves in
such a way as to diminish the repulsion between them.
- Mutual repulsion of two electron clouds forces them to the opposite sides
of a sphere. This is called a linear arrangement.
Example: BeF 2 , berylium fluoride
- Minimum repulsion between three electron pairs occurs when the pairs
are at the vertices of an equilateral triangle inscribed in a sphere. This
arrangement is called a trigonal-planar arrangement.
TIP
These basic arrangements are important to learn!Example: BF 3 , boron trifluoride
- Four electron pairs are farthest apart at the vertices of a tetrahedron
inscribed in a sphere. This arrangement is called a tetrahedral-shaped
distribution of electron pairs.