A molecular orbital that is higher in energy than its constituent atomic
orbitals. Placement of electrons into such orbitals raises the total
energy of the system, making bonding unfavorable.
An orbital that is associated with only one particular atom. This is in
contrast to molecular orbitals, which are spread across a collection of
A molecular orbital that is lower in energy than its constituent atomic
orbitals. Placement of electrons into such orbitals lowers the total
energy of the system, making bonding favorable.
The number of electron pairs involved in a covalent bond. In terms of
Molecular Orbital theory
, it is the number
of bonding electron pairs minus the number of antibonding electron pairs. Larger
bond order means greater bond strength and shorter bond length.
Interaction between atoms held together by the sharing of electrons.
The phenomenon in which electrons are spread out over several atoms or
bonds as opposed to being localized to specific atoms or bonds.
The relative tendency for an atom to attract electrons to itself. Measured
on an arbitrary scale of 4.0, with fluorine being the most electronegative
element. Electronegativity increases from left to right across the periodic
table and decreases as you move down a group.
The linear combination of atomic orbitals into hybrid orbitals that
accommodate particular molecular geometries.
Orbitals formed from the combination of atomic orbitals that accommodate
Lewis Dot structure
A common way to represent molecules, it uses lines to depict bonded electron
pairs and dots to represent lone pairs. Inner shell electrons are not
Orbitals that, in contrast to atomic orbitals, are distributed over an
entire molecule instead of being localized to specific atoms.
Pi bond (Π bond)
Covalent bond formed from the sideways overlap of two p-orbitals.
Sigma bond (σ bond)
Covalent bond formed from the head-on overlap of two orbitals.
Valence bond theory
A theory of covalent bonding that treats bonds as the overlap of atomic
orbitals. A simple extension of Lewis structures.
Valence Shell Electron Pair Repulsion
VSEPR for short. A model that predicts molecular geometry by minimizing
repulsion between adjacent electron pairs.