Are CH3+ and CH3- polar or non-polar molecules? Explain your reasoning using both words and pictures.
The Correct Answer and Explanation is :
Let’s start by analyzing the two molecules, CH₃⁺ (methyl cation) and CH₃⁻ (methyl anion), in terms of their polarity.
CH₃⁺ (Methyl Cation)
A CH₃⁺ molecule is formed when a methyl group (CH₃) loses one electron, leaving it with a positive charge. This molecule is non-polar. Here’s why:
- The carbon atom in CH₃⁺ forms three bonds with hydrogen atoms, creating a trigonal planar molecular geometry.
- However, the positive charge on the carbon atom pulls the electron density towards it, leaving the molecule without any dipole moment (a separation of charge).
- The symmetrical arrangement of the bonds (equal electronegativity between carbon and hydrogen) and the lack of significant charge separation results in no permanent dipole, making CH₃⁺ non-polar.
CH₃⁻ (Methyl Anion)
On the other hand, a CH₃⁻ molecule is formed when a methyl group gains an extra electron, giving it a negative charge. CH₃⁻ is also non-polar, and here’s why:
- Like CH₃⁺, CH₃⁻ has a trigonal planar geometry with three hydrogen atoms attached to the carbon atom.
- The extra electron gives the carbon an increased electron density, but the molecule still has a symmetrical shape, meaning the electron distribution is relatively uniform.
- Even though there is a negative charge on the molecule, the symmetrical bonding and lack of any significant charge separation mean it doesn’t develop a dipole, so it remains non-polar.
Explanation Summary
Both CH₃⁺ and CH₃⁻ are non-polar because of their symmetrical molecular geometries (trigonal planar), which result in no permanent dipole moments despite the presence of charges. The distribution of charge within the molecule is uniform, leading to no significant charge separation.
Now, I’ll generate a diagram to visually represent this.
Here’s the diagram showing the molecular structures of CH₃⁺ (methyl cation) and CH₃⁻ (methyl anion). Both molecules have a trigonal planar geometry with carbon in the center and three hydrogen atoms attached. The positive and negative charges on the carbon atoms are shown, and the symmetry of both molecules is emphasized, which results in their non-polar nature.
