Some molecules w/ non polar bonds like C-S and C-I when exposed to a highly polar environment may assume polarity
-Due to vacant d orbitals of S (i don't get this. So if it has a lot of vacant orbitals it will be polar?)
-big atomic radius of I (please explain this to me)
S and I are included in EN how come it's non polar?
Large molecules, such as I, can be induced to be polar when a highly EN element (such as F or Cl) come close. Smaller molecules don't do that because the electron field is so much closer to the nucleus. The large size of the I atom, however, makes the outer electrons less susceptible to the pull of the protons in the nucleus and more susceptible to a highly polar group approaching from the outside. So the electron field of the I atom can be distorted by a highly EN approaching group.
thanks.. but what does it mean to be induced?
In this case inducing simply means that the highly EN group that gets close to the electronic cloud of the non-polar molecule distorts the cloud to make the molecule polar. That is, the EN group induces a polarity that is not there on its own.
To understand why molecules with nonpolar bonds like C-S and C-I can become polar in a highly polar environment, let's break down the concepts you mentioned.
1. Vacant d orbitals of S: In the case of sulfur (S), it has an atomic number of 16, which means it has electrons occupying the 1s, 2s, 2p, 3s, and 3p orbitals. However, the third energy level or shell of sulfur also has a set of d orbitals (which are higher in energy compared to s and p orbitals). These d orbitals can participate in bonding with other atoms, and if they have vacant spaces, they can accept electron density from other atoms. This acceptance of electron density can contribute to the polarity of the molecule.
2. Big atomic radius of I: In the case of iodine (I), it has an atomic number of 53, making it a larger atom than sulfur. The big atomic radius of iodine means that it has more electron density to share with other atoms. As a result, when iodine is involved in a bond, it can have a greater impact on the overall polarity of the molecule due to its electron density.
Now, regarding your question about electronegativity (EN), it's important to note that the electronegativity difference between two atoms in a bond is what primarily determines if the bond is polar or nonpolar. When the electronegativity difference is small (less than 0.5), the bond is considered nonpolar, and when it's large (greater than 0.5), the bond is considered polar.
In the case of C-S and C-I bonds, the electronegativity difference between carbon (C) and sulfur (S) or iodine (I) is relatively small, which would suggest that the bonds themselves are nonpolar. However, when these molecules are exposed to a highly polar environment (such as a solvent or other polar molecules), they can experience a phenomenon called induced dipole or temporary polarity.
This induced dipole occurs because the highly polar environment generates an electric field that can distort the electron distribution within the molecule. As a result, the electron density shifts, creating temporary polarity within the molecule.
So, while C-S and C-I bonds alone may be nonpolar, the interaction with a polar environment has the potential to induce temporary polarity in the molecule.