Question

Would \(\mathrm{CH}_{3} \mathrm{Cl}\) have any resonance structures? ____________ If so, draw them below.

Short answer

No, CH3Cl does not have any resonance structures. This is because all atoms have fulfilled their respective electron requirements without needing any double or triple bonds, and there are no lone pairs on the central atom (carbon) to be converted into a double or triple bond.

Step-by-step solution

Draw the Lewis structure of CH3Cl

To start, draw the Lewis structure of the molecule. The molecule CH3Cl contains one carbon atom, three hydrogen atoms, and one chlorine atom. Carbon has 4 valence electrons, hydrogen has 1 valence electron, and chlorine has 7 valence electrons. The Lewis structure of CH3Cl, which follows the octet rule, can be represented as: Cl | C - H / \ H H

Examine the molecule's structure

Next, examine the molecule's structure. Carbon, which is bonded to three hydrogen atoms and one chlorine atom, is the central atom in this molecule. All hydrogen atoms have completed their duet rule (2 electrons) and chlorine and carbon have completed their octet rule (8 electrons).

Evaluating the possibility of resonance structures

To have resonance structures, a molecule should have multiple valid and equivalent Lewis structures, distinguished by the position of electrons rather than atoms. In CH3Cl, all atoms have fulfilled their respective electron requirements without needing any double or triple bonds, and there are no lone pairs on the central atom (carbon) to be converted into a double or triple bond. Hence, there aren't multiple ways to distribute the valence electrons in CH3Cl, so it cannot have any resonance structures. In conclusion, CH3Cl does not have any resonance structures.

Key concepts

Lewis Structure

A Lewis structure is a diagram that represents the valence electrons of an atom using dots. It depicts how atoms are bonded together in a molecule and if there are lone pairs of electrons present. To create a Lewis structure, you start by determining the total number of valence electrons available for bonding. For example, in methane (CH₄), carbon has four valence electrons and each hydrogen has one, totaling eight. In the case of chloromethane (CH₃Cl), carbon still has four, each of the three hydrogens has one, and chlorine has seven, which totals to 14 valence electrons to distribute.

Valence electrons are placed around each atom so that they can be shared or belong to only one atom, fulfilling the desire of each non-metal atom to achieve a full outer shell. Single lines represent single bonds, each equivalent to a pair of shared valence electrons. In drawing Lewis structures, certain guidelines must be followed to ensure that the structures conform with known empirical and theoretical principles, such as the octet rule.

Valence Electrons

Valence electrons are the electrons that reside in the outermost shell of an atom, known as the valence shell. These electrons are primarily responsible for an atom's chemical characteristics, as they are the ones directly involved in chemical bonds with other atoms. In simple terms, they are like the atom's 'hands' that reach out to 'hold' other atoms.

The number of valence electrons determines how an element will react with others, and it's this key feature that one uses to draw Lewis structures. In chloromethane, carbon has four valence electrons which it can share with other atoms to form covalent bonds. Chlorine, being in the halogen group, has seven valence electrons and typically gains one more to achieve a full octet, as seen in the molecule CH₃Cl.

Octet Rule

The octet rule is a fundamental concept that states atoms tend to bond in such a way that each atom has eight electrons in its valence shell, resulting in a configuration similar to that of noble gases, which are known for their chemical inertness. It's like each atom desires to 'dress up' as a noble gas, wearing a 'coat' made up of eight electrons.

There are exceptions, mainly with elements that cannot physically accommodate eight electrons due to their position on the periodic table, such as hydrogen which follows the 'duet' rule (full outer shell with two electrons). Nonetheless, in drawing the Lewis structure of chloromethane, you'll see that carbon forms four single bonds, adhering strictly to the octet rule. It shares one electron with each hydrogen and one with chlorine, which allows chlorine to also complete its octet. Since all atoms achieve a stable electron configuration, no alternative structures can exist, indicating no resonance structures are present for this molecule.