To draw the Lewis structure for tellurium tetrafluoride (TeF4), we start by determining the total number of valence electrons. Tellurium (Te) has 6 valence electrons and each fluorine (F) atom has 7 valence electrons. Since there are four fluorine atoms, we have:
Valence electrons from Te: 6
Valence electrons from 4 F: 4 × 7 = 28
Total = 6 + 28 = 34 valence electrons.
Next, we arrange the atoms. Tellurium is the central atom, surrounded by the four fluorine atoms. We then connect each F to Te with a single bond, using 8 electrons (4 bonds × 2 electrons each). Now, we subtract those from the total number of valence electrons:
Total left = 34 – 8 = 26. We then distribute these remaining electrons to fulfill the octets of the four fluorine atoms. Each F needs three lone pairs to complete its octet, which uses 24 electrons (4 fluorine × 6 electrons per F), using up all remaining electrons.
The Lewis structure for TeF4 looks like this:
F F
| |
H - Te - F
|
F
In terms of hybridization, the central atom, tellurium, has four bonded pairs and one lone pair of electrons. The presence of a lone pair means we take into consideration five regions of electron density around the tellurium atom. This leads us to a hybridization state of sp3d.
The electron domain geometry, which considers all electron domains (bonds and lone pairs), is trigonal bipyramidal. However, the molecular geometry is determined by the atoms present, which in this case gives us a see-saw shape due to the lone pair.
As for the bond angles, they are influenced by the molecular shape. The typical bond angles in a trigonal bipyramidal arrangement are 90° and 120°, but the see-saw shape pushes the fluorine atoms closer together, particularly between the F atoms that are 90° apart. Therefore, we expect bond angles around 90° and < 120° for the F-Te-F bonds.
In summary, for TeF4:
- Lewis Structure: Done
- Molecular Geometry: See-saw
- Electron Domain Geometry: Trigonal bipyramidal
- Bond Angles: < 120° and ~90°
- Hybridization: sp3d