To draw the Lewis structure for silicon tetrafluoride (SiF4), we first need to understand the number of valence electrons and the arrangement of atoms.
a. How many valence electrons are there?
Silicon (Si) has 4 valence electrons, and each fluorine (F) has 7 valence electrons. Since there are four fluorine atoms, the total number of valence electrons can be calculated as follows:
4 (Si) + 4 × 7 (F) = 4 + 28 = 32 valence electrons.
b. What is the electron geometry?
The electron geometry for SiF4 is determined by the arrangement of the electron pairs around the silicon atom. Since there are four bonding pairs and no lone pairs, the electron geometry is tetrahedral.
c. What is the molecular geometry?
For SiF4, the molecular geometry is also tetrahedral because all four positions around the silicon atom are occupied by fluorine atoms.
d. What are the hybridized orbitals?
The hybridization of the silicon atom in SiF4 can be described as sp3 hybridization. This occurs because one s orbital and three p orbitals from silicon combine to form four equivalent hybrid orbitals, which are used to form bonds with the fluorine atoms.
e. Is the molecule polar or nonpolar?
SiF4 is a nonpolar molecule. Even though the Si-F bonds are polar due to the difference in electronegativity between silicon and fluorine, the symmetrical tetrahedral shape of the molecule means that the dipole moments cancel each other out, resulting in no overall dipole moment.