Question

Sketch the three-dimensional shape of the following molecules: (a) Methanamine, \(\mathrm{CH}_{3} \mathrm{NH}_{2}\) (b) Iodoform, \(\mathrm{CHl}_{3}\) (c) Ozone, \(\mathrm{O}_{3}\) (d) Phosphorus pentachloride, \(\mathrm{PCl}_{5}\) (e) Chloric acid, \(\mathrm{HClO}_{3}\)

Short answer

Methanamine is pyramidal, iodoform is tetrahedral, ozone is bent, phosphorus pentachloride is trigonal bipyramidal, and chloric acid is trigonal pyramidal.

Step-by-step solution

Understanding Methanamine Structure

Methanamine, \(\mathrm{CH}_{3} \mathrm{NH}_{2}\), consists of a carbon atom bonded to three hydrogen atoms and one nitrogen atom, which in turn is bonded to two hydrogen atoms. This molecule forms a trigonal pyramidal shape around the nitrogen atom due to the lone pair of electrons on nitrogen.

Understanding Iodoform Structure

Iodoform, \(\mathrm{CHl}_{3}\), has a central carbon atom bonded to one hydrogen atom and three iodine atoms. The molecule has a tetrahedral shape around the carbon due to the typical 109.5-degree bond angles in such configurations.

Understanding Ozone Structure

Ozone, \(\mathrm{O}_{3}\), has a bent or V-shape structure. It consists of three oxygen atoms; one central oxygen atom forms single bonds with two other oxygen atoms. The central atom also has lone pairs, which result in a bond angle of approximately 116.8 degrees.

Understanding Phosphorus Pentachloride Structure

Phosphorus pentachloride, \(\mathrm{PCl}_{5}\), consists of a phosphorus atom surrounded by five chlorine atoms. It has a trigonal bipyramidal geometry, where three chlorine atoms are in the equatorial plane, and two are in axial positions.

Understanding Chloric Acid Structure

Chloric acid, \(\mathrm{HClO}_{3}\), consists of a central chlorine atom bonded to one hydroxyl group (OH) and two oxygen atoms. The molecular structure is a trigonal pyramidal shape around the chlorine due to the lone pair on the chlorine atom and the bonding with the hydroxyl group.

Key concepts

Methanamine Structure

Methanamine, with the chemical formula \(\mathrm{CH}_{3}\mathrm{NH}_{2}\), is a simple amine where the molecular structure plays a crucial role in its function and reactivity. Central to methanamine is the carbon atom, bonded to three hydrogen atoms forming a base structure identical to methane. Crucially, the carbon is also connected to a nitrogen atom. This nitrogen atom bears two additional hydrogen atoms, leading to a trigonal pyramidal shape. This geometry is due to the lone pair of electrons on the nitrogen, which repels the bonding pairs of electrons, causing a distortion.

• The overall molecule resembles a distorted tetrahedron.
• It has a bond angle slightly less than 109.5 degrees.

Understanding this pyramid-like shape is essential, as it heavily influences methanamine's chemical behavior and intermolecular interactions.

Iodoform Shape

Iodoform, chemically known as \(\mathrm{CHl}_{3}\), is an organoiodide with an intriguing geometrical arrangement. The core of iodoform is centered around a carbon atom. This carbon makes single bonds with three iodine atoms and one hydrogen atom. This configuration leads to a classic tetrahedral geometry. Tetrahedral geometries are characterized by bond angles close to 109.5 degrees, conforming to the minimal electron repulsion principle known as VSEPR (Valence Shell Electron Pair Repulsion theory).

• The presence of iodine gives iodoform a substantial mass and density.
• The tetrahedral shape ensures the molecule is symmetric and evenly balanced in charge distribution.

This understanding of iodoform’s shape helps predict its solubility and energy interactions in chemical processes.

Ozone Molecule

The structure of ozone, \(\mathrm{O}_{3}\), is unique and slightly more complex than some simple molecules, often depicted with a bent or V-shape. It consists of three oxygen atoms arranged where one oxygen atom is central, bonded to the other two through single bonds. The VSEPR theory explains why the ozone molecule is not linear. The presence of lone pairs on the central oxygen atom distorts the molecular shape, giving it an angle of approximately 116.8 degrees.

• The bent shape results in a polar molecule, where the charges within the molecule are not evenly distributed.
• This shape is crucial in understanding ozone's role in the atmosphere, such as in absorbing ultraviolet radiation.

Grasping the molecular shape of ozone is key to understanding its chemical properties and ecological significance.

Phosphorus Pentachloride Geometry

Phosphorus pentachloride, represented by \(\mathrm{PCl}_{5}\), is a classic example of a molecule with trigonal bipyramidal geometry. The phosphorus atom at the center forms five bonds with chlorine atoms.In this structure, three chlorine atoms occupy equatorial positions forming a triangular plane. The remaining two chlorine atoms are positioned axially, perpendicular to this plane.

• The equatorial bond angles are 120 degrees, while the axial bond angles are 90 degrees.
• Trigonal bipyramidal shapes are unique to molecules with more than four bonds around a central atom.

Understanding its geometry aids in predicting the compound’s reactivity and intermolecular forces in various chemical reactions.

Chloric Acid Structure

Chloric acid \(\mathrm{HClO}_{3}\) has a complex structure that is essential to understand its reactivity and behavior in solutions. The central component of chloric acid is the chlorine atom, which is bonded to one hydroxyl group (OH) and two oxygen atoms.The bonding leads to a trigonal pyramidal shape around the chlorine. This shape occurs as the chlorine atom uses its solitary electron pair to influence the molecular geometry.

• The presence of the OH group significantly impacts the acidity and solubility of chloric acid.
• The resulting structure supports various industrial and chemical processes, especially in bleaching and disinfection.

Appreciating the molecular arrangement of chloric acid helps in understanding its chemical properties and potential applications.