8th - heteronuclear and Polyatomic Molecules Flashcards
how does the AO energy change across and period and why
from left to right the energy decreases
stronger nuc charge = attracts the electrons more
the greater the elements electronegativity
the lower energy AO it has
its line in an MO is lower than the other elements
why is phosphorus pentaflouride hypervaent and why doesnt the lewis structure work for it
P shares its 5 valence e-
each F also shares 1 e-
this gives P 10 outer electrons
it has an expanded octet rule
however it is still stable
what is a bond order
number of bonds between a pair of atoms
symbol for electronegativity
chi
x
higher oxidation state means
higher electronegativity
more positive = attracts e- more
what does the schrodinger equation do
makes it possible to describe e-
for H only!!
2 body system: 1 e- 1proton
what makes sp hybrids
s (2e-)
pz (1e-)
directional
overlap of 2 sp hybrids gives
1 sigma bond (sp overlap)
2 double bonds (normal px and py overlap)
giving a bond order of 3
what approach are mo formed by
linear combination of atomic orbitals
LCAO
how do atomic orbitals have wave properties such as interpherence
ao are single electron wavefunctions and therefore have wave properties
such as constructive and destructive interference between different atomic orbitals
constructive interpherence
in phase combo
amplitude increases
add ao
destructive interference
out of phase combo
cancel out
subtract ao
bonding orbital
in phase combo
addition of ao
higher e- density between the 2 nuclei than before (holds them together)
larger wavefunction than before
bond has been formed
if bond enthalpy increases what happens to the bond
bond order increases (double, triple)
bond length decreases (triple is shorter than single)
