What is the molecular geometry of the molecule TeF_4?

• A. Tetrahedral
• B. Trigonal bipyramidal
• C. See-saw
• D. Square planar

Answer: (C)

Verified step by step guidance

1. Step 1: Determine the Lewis structure of TeF_4. Tellurium (Te) is the central atom bonded to four fluorine (F) atoms. Count the total valence electrons: Te has 6 valence electrons, each F has 7, so total electrons = 6 + 4 × 7 = 34 electrons.
2. Step 2: Draw single bonds between Te and each F atom, using 8 electrons (4 bonds × 2 electrons). Distribute the remaining electrons to complete the octets of the fluorine atoms first, then place any leftover electrons on the central atom (Te).
3. Step 3: Count the regions of electron density (bonding and lone pairs) around the central atom. Te has 4 bonding pairs (to F atoms) and 1 lone pair, making a total of 5 regions of electron density.
4. Step 4: Use VSEPR theory to predict the electron geometry and molecular geometry. Five regions of electron density correspond to a trigonal bipyramidal electron geometry. The presence of one lone pair changes the molecular geometry from trigonal bipyramidal to see-saw.
5. Step 5: Conclude that the molecular geometry of TeF_4 is see-saw, which matches the correct answer choice.