VSEPR & Molecular Geometry
A molecule with 5 electron groups and 2 lone pairs on the central atom will have what molecular geometry?
T-shaped
What determines whether a bond is polar covalent vs nonpolar covalent?
The difference in electronegativity between atoms
What hybridization corresponds to a tetrahedral electron geometry?
sp3
What formula is used to calculate bond order using MO theory?
Bond Order= (bonding electrons - antibonding electrons)/2
What is the formula for molarity?
M = (moles of solute/liters of solution)
What molecular geometry results when a trigonal bipyramidal molecule contains one lone pair on the central atom?
Seesaw
Why is CO₂ nonpolar even though each C=O bond is polar?
The molecule is linear, so the two dipoles cancel each other out.
How many sigma and pi bonds are in C₂H₄ (ethylene)?
5 sigma bonds and 1 pi bond
What bond order indicates that a molecule is stable?
Any bond order greater than zero
What equation is used for dilution calculations?
C1V1=C2V2
Why do lone pairs prefer equatorial positions in trigonal bipyramidal structures?
Equatorial positions experience fewer repulsions (2 at 90°) than axial positions (3 at 90°).
Between NH₃, BF₃, and H₂O, which molecule has the largest dipole moment?
H₂O, because it has a bent shape and strong bond polarity, creating a large net dipole
Why are pi bonds generally weaker and more reactive than sigma bonds?
Pi bonds involve side-to-side orbital overlap, which is weaker than the end-to-end overlap of sigma bonds.
Why is O₂ paramagnetic according to molecular orbital theory?
Because it contains two unpaired electrons in antibonding π* orbitals.
What precipitate forms when AgNO₃(aq) reacts with NaCl(aq)?
AgCl(s)
Predict the molecular geometry and bond angles of ClF₃.
T-shaped, with bond angles approximately 90° and 180°.
Is XeF₂ polar or nonpolar?
Nonpolar
What hybridization occurs for carbon atoms in acetylene (C₂H₂)?
sp hybridization
Which species has the greater bond order: O₂⁺ or O₂⁻?
O₂⁺
Removing an electron removes it from an antibonding orbital, increasing bond order.
Identify the oxidizing agent in this reaction:
Zn+Cu2+→Zn2++Cu
Cu²⁺
It gains electrons and is reduced.
A molecule has six electron groups around the central atom and two lone pairs opposite each other. What is the molecular geometry?
Square planar
A molecule contains several polar bonds but has no overall dipole moment. What must be true about the molecule?
The molecule must have a symmetrical geometry that cancels dipoles.
Why do unhybridized p orbitals form π bonds instead of hybrid orbitals?
Hybrid orbitals are used for sigma bonding, leaving unhybridized p orbitals available for side-by-side overlap, forming π bonds.
A diatomic molecule has 10 valence electrons (like N₂). What are its bond order and magnetic properties?
Bond order = 3
Magnetic behavior = Diamagnetic
Write the net ionic equation when BaCl₂(aq) reacts with Na₂SO₄(aq).
Ba2+(aq)+SO42−(aq)→BaSO4(s)