Bond Energy/Length

Single Bond

1 line/1 sigma bond

Double Bond

2 lines/1 sigma & 1 pi bond

Triple Bond

3 lines/1 sigma & 2 pi bonds

Increasing Bond Length

Triple

Increasing Bond Strength

Single

Bond Order (general)

total # of individual bonds/# of bond areas

* the closer to 0 the better the structure

Formal Charge

group #-dots-sticks

Bond Energy

deltaHrxn= sum of reactants - sum of products

Lattice Energy

• increases as atoms get smaller

• ion1 charge * ion2 charge

  • high LE means high melting and boiling point

Valence Bond Theory

• of e- groups = # of hybrid orbitals

• look at partially filled/empty orbitals to determine overlap

  • double/triple bonds are 1 e- group

Sigma Bond

end to end, lowers overall energy, allows free rotation

* stronger than pi bonds

Pi bond

side by side, restricts rotation

Molecular Orbital Theory

Treats a molecule as a collection of atomic nuclei with orbitals that are delocalized over the entire molecule, thereby eliminating the need for resonance structures to depict molecules with fractional bond orders.

pi = 2 boxes

sigma = 1 box

Bond Order (Molecular Orbital ONLY)

Bond Order = 1/2(bonding-antibonding\*)

* the greater it is the more stable