The sulfur and oxygen in methanethiol and methanol are both sp 3 hybridized. Why is the S―H bond longer than the O―H bond?

Hi, everybody. Let's look at it. The next problem explain why the S H bond in ethane viol is longer than the O H bond in ethanol. If the S and O in the mentioned compounds are both S P three hybridized. And then we're given just chemical structures of both compounds. Ethane biol and ethanol both have two carbons. And then Ethane viol has an S H group bonded to one of the carbons. While ethanol of course has an O H group choice, a sulfur has a larger atomic radius than oxygen leaving the S H bond and methane dial to be longer compared to the O H bond. And ethanol choice B oxygen has a higher ionization energy than sulfur leading the O H bond and ethanol to be shorter than the S H bond. And ethane vial choice C sulfur has a higher electron affinity than oxygen leading the SHH bond and ethane vial to be stronger than the bond in ethanol. And then choice D oxygen has a larger electron negativity than sulfur leading the O H bond in ethanol to be more polar than the S H bond. And ethane pile. Well, to evaluate our answer choices, we need to think about what determines bond length in a compound. And bond length is the distance between the nuclei of two covalent bonded atoms as we have here, the S H bond and the O H bond are both covalent bonds. And the bond length is thus approximately equal to the sum of the atomic radii of the two atoms. So the key quantity we want to look at, look at here when determining what it would say why one bond length is greater. The other is the size of the atomic radius of our atoms involved in our bonds. Well, we've got hydrogens in both cases. So that obviously will be the same for both. It's just what's the difference between the atomic radius of sulfur versus oxygen? Well, atomic radius is one of those qualities that does have periodic trends on our periodic table. Uh So let's think about sulfur and oxygen on the periodic table. And of course, sulfur and oxygen are in the same column of the periodic table. So we don't need to worry about left versus right trends of atomic radius, but sulfur is one row below oxygen on the periodic table, an atomic radius increases down the periodic table. That's because we're adding more energy levels. And therefore our electron clouds clouds are growing larger. So sulfur is atomic radius is larger. So sulfur has a larger atomic radius. When we look at our answer choices, we almost didn't even have to go through all that and figure that out because there's only one of our choices that talks about atomic radius. A choice. A choice B is talking about the ionization energy of oxygen, but we're not talking about an ionic bond. We're talking about a covalent bond. So we're not interested in. Choice. B. Choice C is talking about the electron affinity of sulfur. Well, that may determine the polarity of our bond, but we're just interested in the atomic radius. So choice C is not our answer. And finally, choice D says that oxygen has a larger electron electron negativity making the bond more polar. But we're not comparing the polarity of the bond. We're comparing the bond length. So we just need to look at atomic radius. So our answer here is the one answer. Choice that deals with atomic radius. And it is indeed correct. Choice. A sulfur has a larger atomic radius than oxygen leading the S H bond and ethane dial to be longer compared to the O H bond. And ethanol. See you in the next video.

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1. A Review of General Chemistry5h 5m
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Problem 43

Textbook Question

The sulfur and oxygen in methanethiol and methanol are both sp³ hybridized. Why is the S―H bond longer than the O―H bond?

Verified step by step guidance

Understand the concept of bond length: Bond length is the distance between the nuclei of two bonded atoms. It depends on the size of the atoms and the type of bond (single, double, etc.). Larger atoms tend to form longer bonds because their electron clouds are more spread out.

Compare the atomic sizes of sulfur (S) and oxygen (O): Sulfur is in Period 3 of the periodic table, while oxygen is in Period 2. Atoms in Period 3 are larger than those in Period 2 because they have an additional electron shell. This means sulfur has a larger atomic radius than oxygen.

Relate atomic size to bond length: Since sulfur is larger than oxygen, the S―H bond will naturally be longer than the O―H bond. The larger size of sulfur increases the distance between the sulfur nucleus and the hydrogen nucleus compared to the oxygen-hydrogen bond.

Consider hybridization and bond type: Both sulfur and oxygen in methanethiol and methanol are sp³ hybridized, meaning they form single bonds with hydrogen. The hybridization does not significantly affect the bond length in this case, as the difference is primarily due to the atomic size of sulfur and oxygen.

Conclude the reasoning: The S―H bond is longer than the O―H bond because sulfur is a larger atom than oxygen, leading to a greater bond length due to the increased distance between the bonded nuclei.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Hybridization

Hybridization is the concept in organic chemistry that describes the mixing of atomic orbitals to form new hybrid orbitals. In the case of methanethiol and methanol, both sulfur and oxygen are sp³ hybridized, meaning they form four equivalent orbitals for bonding. This hybridization influences the geometry and bond characteristics of the molecules.

Bond Length

Bond length refers to the distance between the nuclei of two bonded atoms. It is influenced by factors such as atomic size, bond order, and the presence of lone pairs. In general, larger atoms form longer bonds; thus, the S―H bond in methanethiol is longer than the O―H bond in methanol due to sulfur's larger atomic radius compared to oxygen.

Electronegativity

Electronegativity is a measure of an atom's ability to attract and hold onto electrons in a bond. Oxygen is more electronegative than sulfur, which affects the bond character. The stronger attraction in the O―H bond leads to a shorter bond length compared to the S―H bond, where the weaker attraction results in a longer bond.

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