1.Use the Vsepr theory to predict and explain the shape and bond angle of each of the molecules SCI2 and C2CL2.
2.Deduce whether or not each molecule is polar, giving a reason for your answer...Any help please??
SCl2 has a tetrahedral electronic structure (like H2O) and is bent (like H2O). It is polar.
I can hazard a guess for C2Cl2. I never heard of such a molecule. That makes C with an oxidation state of +1. Most unusual.
I CAN'T hazard......
C2Cl2 = dichloroacetylene. Both C's are sp-hybridized. So, what's so unusual about this compound (other than the fact that it stinks and is pyrophoric)?
To predict the shape and bond angle of molecules using the VSEPR (Valence Shell Electron Pair Repulsion) theory, you need to follow these steps:
1. Draw the Lewis structure of the molecule.
2. Determine the number of electron groups around the central atom (including lone pairs and bonded atoms).
3. Identify the molecular geometry based on the number of electron groups.
4. Predict the bond angles based on the molecular geometry.
Let's apply these steps to the molecules SCI2 and C2CL2:
1. SCI2
Start by drawing the Lewis structure of SCI2:
S is the central atom. It has 6 valence electrons, while each Cl atom contributes 7 valence electrons. Adding them up, we have:
6 + 2(7) = 20 valence electrons.
Sulfur (S) is the central atom:
Sulfur forms single bonds with each of the two chlorine (Cl) atoms:
Cl
|
Cl — S — Cl
Place the remaining 14 valence electrons around the Cl atoms as lone pairs.
Adding the lone pairs forms the structure:
Cl
|
Cl — S — Cl
Here, Sulfur has one lone pair, and the Cl atoms have three lone pairs each.
2. Determine the number of electron groups around the central atom:
In SCI2, there are two bonded atoms (Cl) and one lone pair, giving a total of three electron groups around the central atom.
3. Identify the molecular geometry:
With three electron groups, the molecular geometry is trigonal planar.
4. Predict the bond angles:
In a trigonal planar geometry, the bond angles are approximately 120 degrees.
Next, let's analyze the molecule C2CL2:
Carbon (C) is the central atom. It has 4 valence electrons, while each Cl atom contributes 7 valence electrons. Adding them up, we have:
2(4) + 2(7) = 30 valence electrons.
Carbon (C) is the central atom:
Carbon forms single bonds with each of the two chlorine (Cl) atoms:
Cl
|
Cl — C — Cl
Place the remaining 26 valence electrons around the Cl atoms as lone pairs.
Adding the lone pairs forms the structure:
Cl
|
Cl — C — Cl
Here, each Carbon has one lone pair, and the Cl atoms have three lone pairs each.
2. Determine the number of electron groups around the central atom:
In C2CL2, there are two bonded atoms (Cl) and two lone pairs on each Carbon, giving a total of four electron groups around the central atom.
3. Identify the molecular geometry:
With four electron groups, the molecular geometry is tetrahedral.
4. Predict the bond angles:
In a tetrahedral geometry, the bond angles are approximately 109.5 degrees.
Now, let's determine if these molecules are polar or nonpolar:
For a molecule to be polar, it must have an unsymmetrical distribution of charge, usually due to a difference in electronegativity between the atoms involved in the bonds.
Looking at SCI2:
Sulfur (S) and Chlorine (Cl) have different electronegativities. Since Sulfur has a lone pair, the electron distribution is asymmetrical, making the molecule polar.
Now, let's look at C2CL2:
Carbon (C) and Chlorine (Cl) have different electronegativities. Although there are two Chlorine atoms on each side, their electron distribution is symmetric, making the molecule nonpolar.
In summary:
1. SCI2 has a trigonal planar shape with bond angles of approximately 120 degrees. It is polar due to its asymmetrical electron distribution.
2. C2CL2 has a tetrahedral shape with bond angles of approximately 109.5 degrees. It is nonpolar due to its symmetrical electron distribution.