molecular orbitals Flashcards
molecular orbital theory (MO)
the atomic orbitals of atoms merge as two atoms approach to form a new set of molecular orbitals (one bonding, HOMO, and one anti bonding, LUMO)
does HOMO or LUMO have the higher energy
LUMO
s orbitals
MO’s formed by end on overlap of atomic orbitals along the axis of a covalent bond are known as sigma bonds
constructively interfere
sigma bonding orbital
destructively interfere
anti bonding sigma bonding orbital
what orbitals can form sigma bonds
s, p and sp
pi bonds
p orbitals can also combine by side on overlap to produce pi bonding and pie anti bonding
difference between sigma and pi
pi bonds are weaker and lie perpendicular to sigma bonds
when is a HOMO structure stable
when it contains a bonding orbital and if it contains an anti bonding orbital it is not likely to exist
when are MO symmetrical
in a non polar covalent bond as the electrons are evenly distributed
when are MO asymmetrical
in a polar covalent bond as electrons are unevenly distributed
in a MO diagram the atom with the largest electronegativity…
will have the bonding electron at the lowest energy
