topic 11 -valence bond theory

What is valence bond theory?

says that bonds are formed by the simple overlap of atomic orbitals on 2 nuclei

when does hybridization occur

occurs when electrons are shared between 2 nuclei

how to determine the hybridization of an atom?

count the number of atoms connected to the atom you’re focused on

count number of lone pairs on the focused atom

add the two numbers together

the exponents should add up to the sum calculated above

what electron geometry is associated with the hybridization sp?

linesr

what electron geometry is associated with the hybridization sp²?

trigonal planar

what electron geometry is associated with the hybridization sp³?

tetrahedral

what electron geometry is associated with the hybridization dsp³?

trigonal bipyramidal

what electron geometry is associated with the hybridization d²sp³?

octahedral

the total number (n) of hybrid orbitals can be identified by

adding the exponents together

all bonds contain

at least one sigma bond

what needs to occur to form a sigma bond?

• orbitals overlap constructively

• head on overlap (orientation matters)

triple bonds contain how many sigma bonds and how many pi bonds?

2 pi bonds

1 sigma bonds

double bonds contain how many sigma bonds and pi bonds?

1 sigma bond and 2 pi bonds

what is an isomer?

same chemical formula, but different spatial arrangement

free rotation about the single bond means that …

there is no diapole moment for the molecule / tends to be symmetrical