Question

1. answer the below questions for the sef₄ molecule:

a. report the total number of valence electrons in the structure:
b. draw the lewis structure:

c. what is the electronic geometry?
d. what is the molecular shape and bond angles?

1. the below image is a lewis structure for caffeine, identify the molecular geometries and bond angles around the indicated atoms

(image of caffeines lewis structure)

Explanation:

Part 1: $\ce{SeF4}$ Molecule

1a. Total Valence Electrons

Step1: Find valence electrons of Se and F.

Se (Group 16) has 6 valence e⁻; F (Group 17) has 7 valence e⁻.

Step2: Calculate total.

$\ce{SeF4}$ has 1 Se and 4 F.
Total = $6 + (4 \times 7) = 6 + 28 = 34$.

Step1: Central atom (Se) bonds to 4 F.

Se is central. Connect Se to 4 F with single bonds (4 bonds, 8 e⁻ used).

Step2: Distribute remaining electrons.

Remaining e⁻: $34 - 8 = 26$. F needs 6 more e⁻ (3 lone pairs each; 4 F × 6 = 24 e⁻). Se gets 1 lone pair (2 e⁻).
Lewis structure: Se (1 lone pair) bonded to 4 F (each with 3 lone pairs).
(Visual: Se in center, 4 F around, Se has one lone pair, F has three lone pairs each.)

1c. Electronic Geometry

Step1: Determine electron groups around Se.

Se has 4 bonding groups (to F) and 1 lone pair → total 5 electron groups.

Step2: Match to VSEPR geometry.

5 electron groups → trigonal bipyramidal electronic geometry.

Answer:

34

1b. Lewis Structure