The bulk modulus of polystyrene is 3.43GPa. Calculate the hydrostatic pressure (stress) needed for a sample of this material to change volume by 1.0 per cent.
• orbitals are the area of space where an electron can be found • atomic orbitals are orbitals belonging to a single atom • molecular orbitals are orbitals belonging to a single molecule, electrons no longer localized on a single atom • overlap of like phase s orbitals (constructive)—>bonding molecular orbital (or σ orbital) • overlap of opposite phase s orbitals (deconstructive)—>antibonding molecular orbital (or σ* orbital) —if filled, the bond between nuclei weakens and eventually breaks canceled region of antibonding orbital forms node - region with no e- density • when 2 orbitals overlap both bonding and antibonding orbitals are formed bond order = (bonding e-) - (antibonding e-) 2 *bonding orbital filled first • antibonding orbitals break their corresponding bonding orbitals when filled 2 possible ways p orbitals can overlap (pi or pi* orbitals) • —perpendicular: equal bonding and antibonding, so they cancel—> no molecular orbital formed —parallel: more bonding or antibonding orbitals • guidelines for molecular orbital construction —# orbitals produced = # orbitals you start with A. need to be able to hold same # of e- —better overlap of orbitals—>stronger interaction/bon
