Chapter 9: Molecular Geometry and Bonding Theories Flashcards
What are the bond angles in a tetrahedron molecular shape?
109.5 degrees
what is the MOLECULAR geometry for a molecule with THREE bonding domains and no non-bonding domains?
trigonal planar (flat)
Does bond enthalpy go up or down as bond order goes up?
up (as bond enthalpy is the energy needed to break 1 mole’s worth of a given bond)
what is the MOLECULAR geometry for a molecule with THREE bonding domains and TWO non-bonding domains?
t shaped
What are the bond angles in a linear molecular shape?
180 degrees
what is the MOLECULAR geometry for a molecule with FOUR bonding domains and no non-bonding domains?
tetrahedral
what is the MOLECULAR geometry for a molecule with FOUR bonding domains and ONE non-bonding domains?
seesaw
What are the bond angles in a trigonal planar molecular shape?
120 degrees
What are the bond angles in a trigonal BI-pyramid molecular shape?
120 degrees and 90 degrees
what is the ELECTRON geometry for a molecule with TWO electron domains?
linear
Where do non-bonding electron pairs live in the octahedron molecular shape?
In the axial (up and down) plane
what is the MOLECULAR geometry for a molecule with FIVE bonding domains and no non-bonding domains?
trigonal bypyramid
Does a bond order of 1/2 mean that 1/2 of a bond will form between two atoms?
Not necessarily. I means that the atoms involved in this particular molecular orbital are slightly more stable/have slightly less energy than they do as two separate atoms.
what is the MOLECULAR geometry for a molecule with FIVE bonding domains and THREE non-bonding domains?
linear
because the non-bonding domains occur equatorially
Do anti-bonding originals cancel out the bond-stregnthening effects of bonding orbitals?
Yes, especially if the electrons in non-bonding orbitals outnumber the electrons in bonding orbitals.
Which range of bond order values tell you that some level of bonding is likely to occur?
All bond order values greater than 0 indicate that some level of bonding is likely to occur
Where do non-bonding electron pairs live in the trigonal bipyramid molecular shape?
in the equatorial (around) plane
What are the bond angles in a octahedral molecular shape?
90 degrees
According to molecular orbital theory, how does energy predict whether bonds will occur between atoms?
The energy of involved in having electrons in bonding molecular orbitals is LOWER than the energy involved in keeping the electrons in separate, regular regular atomic orbitals
This is true even when some electrons wind up in non-bonding molecular orbitals, provided the non-bonding orbitals don’t outnumber the bonding orbitals.
Is bond order the only factor that plays into bond enthalpy and bond length?
No, Things like Zeff and orbital overlap also play a role
Can you have fractions for bond orders?
Yes
what is the MOLECULAR geometry for a molecule with TWO bonding domains and ONE non-bonding domains?
bent
what is the ELECTRON geometry for a molecule with FOUR electron domains?
tetrahedral
How/why does increasing the number of electrons in an anti-bonding orbitals DECREASE a molecule’s bond stability?
If anti-bonding electrons outnumber the bonding electrons, the net effect is that a bond is LESS likely to occur (b/c the wave functions for the electrons aren’t lining up just right to give rise to CONSTRUCTIVE wave combination)
