Molecular Geometry
Electron-Domain Geometry (Base Geometry)
Bond Angles
The VSEPR Model
Valence-Bond Theory & Molecules
100

This is the molecular geometry of the central atom in CF4.

What is tetrahedral?

100

This is the electron-domain geometry of the central atom in BF3.

What is trigonal planar?

100

This is the bond angle produced in an octahedral molecular geometry.

What is 90 degrees?

100
The acronym VSEPR stands for this phrase.
What is Valence-Shell Electron-Pair Repulsion?
100

These are the covalent bonds in which the electron density lies along the line connecting the atoms.  (They bond end to end.)

What are sigma bonds?

200
This is the molecular geometry of the central atom in SO2.
What is bent?
200

This is the electron-domain geometry of the central atom in NO2-.

What is bent (109.5o)?

200

This is the bond angle produced in a square planar molecular geometry.

What is 90 degrees?

(It is the octahedral geometry with 2 of the six positions as electron pairs - so "square planar."

200

What geometry has 5 electron groups around the central atom?

What is Trigonal Bipyramidal?

200

Bonds that are formed from the side-to-side overlap of unhybridized p orbitals.

What are pi bonds?

300

This is the molecular geometry of the central atom in BCl3.

What is trigonal planar?

300
This is the electron-domain geometry of the central atom in SF2.
What is tetrahedral?
300

This is the axial-equatorial bond angle produced in a seesaw molecular geometry.  (HINT:  See-Saw is not an Octet-forming central angle.)

What is less than 90 degrees?

300

According to the VSEPR model, electron domains orient themselves to minimize these.

What are electrostatic repulsions?  (From both bonding electrons and electron pairs.)

300

This is the number of sigma and pi bonds in a typical triple bond.

What is 1 sigma and 2 pi?

single bonds -> 1 sigma
double bonds -> 1 sigma 1 pi
triple bonds -> 1 sigma, 2 pi

Memorize these!

400
This is the molecular geometry of the central atom in KrBr2.
What is linear?
400
This is the electron-domain geometry of the central atom in ClF3.
What is trigonal bipyramidal?
400

This is the bond angle produced in NF3.

Four electron groups.  What is less than 109.5 degrees?

400

This is the period on the periodic table that molecules with expanded valence shells (more than octet) begin to appear.

What is the third period? (This is the energy level where d electrons begin to appear.  Without d electrons, we can only have octets, or duets).

400

The carbon-carbon sigma bond in ethylene, CH2CH2, results from the overlap of these hybrid orbitals.

(Determine the molecular geometry and you're there.)

We want to know what the hybridization is for CH2CH2.

What are sp2.  (The molecular geometry is 1200 - three electron groups.)

500
This is the molecular geometry of the central atom in phosphorus pentafluoride.
What is trigonal bipyramidal?
500

This is the electron-domain geometry of the central atom in BrF4-.  (This is an Octet Exception)

What is octahedral?

500

This is the O-N-O bond angle produced in the nitrate ion.  NO3-

3 bonds -> 3 things -> What is 120 degrees?

500

This is the Cl-C-O bond angle produced in the COCl2.

What is greater than 120 degrees?

500

Determine the hybridization of the bonds in the central atom of C2H2.  (Get the molecular geometry and you're there.)

What is sp hybridization?  (It's a linear molecule, which is non-polar, by the way.)

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