Lewis dot structure for TeF6
The correct answer and explanation is:
Lewis Dot Structure of Tellurium Hexafluoride (TeF₆)
- Central Atom: Tellurium (Te) is the central atom because it is less electronegative than fluorine.
- Valence Electrons:
- Tellurium (Te) has 6 valence electrons.
- Each fluorine (F) atom has 7 valence electrons, contributing 6 × 7 = 42 electrons.
- Total valence electrons = 6 + 42 = 48 electrons.
- Structure Formation:
- Place Te in the center and arrange six F atoms around it.
- Form a single bond between Te and each F atom. Each bond uses 2 electrons × 6 bonds = 12 electrons.
- The remaining 36 electrons are placed as lone pairs around the six F atoms (6 × 6 = 36 electrons) to satisfy their octet rule.
- Octet Expansion:
- Tellurium belongs to Period 5 and has d-orbitals, allowing it to accommodate more than 8 electrons. In TeF₆, Te has 12 electrons around it (6 bonding pairs), expanding its octet.
Explanation
Tellurium hexafluoride (TeF₆) is a molecule where the central atom, tellurium (Te), is surrounded by six fluorine (F) atoms in an octahedral geometry. The Lewis structure provides a two-dimensional representation of the molecule’s bonding.
Tellurium has six valence electrons, and each fluorine atom has seven valence electrons. By forming six single covalent bonds with fluorine, tellurium uses all its valence electrons. Each fluorine atom requires one more electron to complete its octet, which it achieves by sharing one electron with tellurium.
The resulting structure shows tellurium at the center with six single bonds extending to fluorine atoms. The molecule uses all 48 valence electrons—12 for the bonds and 36 as lone pairs on fluorine atoms.
TeF₆ demonstrates the ability of elements from Period 3 and beyond to expand their octet due to the availability of d-orbitals. Tellurium’s expanded octet accommodates 12 electrons because it can promote electrons to empty 5d orbitals, forming additional bonds.
The geometry of TeF₆ is octahedral, dictated by the arrangement of six electron domains around the central tellurium atom to minimize electron repulsion (VSEPR theory). This structure results in bond angles of 90°.
TeF₆ is a highly symmetrical and nonpolar molecule. While each Te-F bond is polar due to the electronegativity difference, the symmetry of the octahedral shape cancels out the dipoles, making the molecule nonpolar.