Question

ws: molecular geometry
directions: you may use your vsepr chart and notes to answer the following questions.

1. what does vsepr stand for?
2. what does the vsepr theory state?
3. draw the lewis dot structure for each of the following molecules. use the vsepr theory to determine

the shape and identify what shape it is.

Explanation:

1. VSEPR is an acronym. By knowing common chemistry acronyms, we can recall that it stands for Valence - Shell Electron - Pair Repulsion.
2. The VSEPR theory is about molecular geometry. It states that electron pairs (both bonding and non - bonding) around a central atom will arrange themselves to minimize repulsion, which in turn determines the shape of the molecule.

3.

• For \(F_2\):
• Lewis dot structure: Each \(F\) atom has 7 valence electrons. They form a single covalent bond. So the Lewis structure is \(F - F\) with three lone pairs on each \(F\) atom (\(:F - F:\)).
• Molecular geometry: Since there are only two atoms, it is linear.
• VSEPR shape name: Linear.
• For \(H_2S\):
• Lewis dot structure: \(S\) has 6 valence electrons and \(H\) has 1. \(S\) forms two single bonds with \(H\) atoms. The Lewis structure is \(H - S - H\) with two lone pairs on \(S\) (\(H:S:H\)).
• Molecular geometry: The two bonding pairs and two lone pairs around \(S\) give a bent shape.
• VSEPR shape name: Bent (or V - shaped).
• For \(CH_4\):
• Lewis dot structure: \(C\) has 4 valence electrons and \(H\) has 1. \(C\) forms four single bonds with \(H\) atoms. The Lewis structure is \(H - C - H\) with all \(H\) atoms around \(C\) (\(

$$\begin{matrix}H\\|\\H - C - H\\|\\H\end{matrix}$$

\)).

• Molecular geometry: Four bonding pairs and no lone pairs around \(C\) give a tetrahedral shape.
• VSEPR shape name: Tetrahedral.
• For \(CCl_4\):
• Lewis dot structure: \(C\) has 4 valence electrons and \(Cl\) has 7. \(C\) forms four single bonds with \(Cl\) atoms. The Lewis structure is \(Cl - C - Cl\) with all \(Cl\) atoms around \(C\) (\(

$$\begin{matrix}Cl\\|\\Cl - C - Cl\\|\\Cl\end{matrix}$$

\)).

• Molecular geometry: Four bonding pairs and no lone pairs around \(C\) give a tetrahedral shape.
• VSEPR shape name: Tetrahedral.

Answer:

1. Valence - Shell Electron - Pair Repulsion
2. Electron pairs around a central atom arrange to minimize repulsion, determining molecular shape.

3.

Molecule	Lewis Dot Structure	Molecular Geometry (Shape)	VSEPR Shape Name
\(H_2S\)	\(H:S:H\)	Bent (V - shaped)	Bent (V - shaped)

| \(CH_4\) | \(

$$\begin{matrix}H\\|\\H - C - H\\|\\H\end{matrix}$$

\) | Tetrahedral | Tetrahedral |
| \(CCl_4\) | \(

$$\begin{matrix}Cl\\|\\Cl - C - Cl\\|\\Cl\end{matrix}$$

\) | Tetrahedral | Tetrahedral |