Draw and Explain the Lewis Structure of SeF2: Determine Its Molecular Geometry, Hybridization, Bond Angles, and Polarity

To draw the Lewis structure of selenium difluoride (SeF₂), we first need to account for the valence electrons. Selenium is in group 16 and has 6 valence electrons, while each fluorine atom (Fl) has 7 valence electrons. Therefore, the total number of valence electrons in SeF₂ is:

6 (from Se) + 2 × 7 (from 2 F) = 20 valence electrons.

When constructing the Lewis structure, we place selenium in the center and bond it to the two fluorine atoms:

1. Draw two single bonds (S-F) connecting Se to each F. This uses 4 electrons (2 for each bond).

2. Subtract these 4 electrons from the total, leaving us with 16 electrons remaining.

3. Next, complete the octets of the fluorine atoms by adding 6 electrons to each, since each F needs 8 electrons to complete its octet.

4. Once you place 6 electrons around each fluorine, we have now used up all the remaining 16 electrons, as each F uses 3 lone pairs (6 electrons).

At this point, selenium only has 4 electrons around it, so we place 2 lone pairs of electrons on Se. This representation satisfies the octet rule for the fluorine atoms and has the following Lewis structure:

Now, let’s analyze the molecular geometry. The SeF₂ molecule has a total of 4 regions of electron density around the central selenium atom: 2 bonding pairs (with fluorine) and 2 lone pairs. According to the VSEPR theory, this arrangement leads to a tetrahedral electron geometry. However, due to the presence of the lone pairs, the molecular shape becomes bent or angular.

The hybridization of selenium in SeF₂ can be classified as sp³. This is because we have 4 regions of electron density (including lone pairs) around the central atom.

The bond angle in SeF₂ is approximately 103 degrees, which is slightly less than the ideal tetrahedral angle of 109.5 degrees due to lone pair repulsion being stronger than bonding pair repulsion.

Regarding polarity, SeF₂ is a polar molecule. This is due to the electronegativity difference between selenium and fluorine, as fluorine is more electronegative. The molecular geometry is bent, which means that the dipoles do not cancel out, creating an overall molecular dipole moment.

In summary:

• Lewis Structure: Two fluorines bonded to selenium with two lone pairs on selenium.
• Molecular Geometry: Bent.
• Hybridization: sp³.
• Bond Angles: Approximately 103 degrees.
• Polarity: Polar molecule.