VSEPR Molecular 3D Structure Model (Valence Shell Electron Pair Repulsion Model Kit)

Model:

VSEPR Molecular 3D Structure Model (Valence Shell Electron Pair Repulsion Model Kit)

Applicable Scope:

High school chemistry selective compulsory "Structure and Properties of Matter," college general chemistry teaching. Used to explain core knowledge points such as valence shell electron pair repulsion theory (VSEPR), molecular spatial configuration, and lone electron pairs. Suitable for teacher demonstrations and student group experiments.

Principle:

Core of VSEPR theory: The spatial configuration of a molecule is determined by the repulsion between bonding electron pairs and lone electron pairs of the central atom. In addition to conventional atom spheres and chemical bond connecting rods, this model set is additionally equipped with lone pair lobe-shaped components to simulate invisible lone electron pairs, visually demonstrating the squeezing effect of lone electron pairs on bond angles, and distinguishing electron pair geometry from molecular spatial configuration.

Product Components:

1. Atom Spheres (50 pieces total) - Central Atom: Gray sphere (23 mm diameter) – used to construct the molecular core (e.g., C in CH4 N in NH3). - Ligand Atoms: Available in multiple colors corresponding to different elements: - White (H, 17 mm): 10 pieces – simulates hydrogen atoms. - Red (O, 17 mm): 8 pieces – used for water, carboxylic acids, etc. - Green (Cl, 17 mm): 6 pieces – constructs halogenated hydrocarbons and inorganic acids. - Blue (N, 17 mm): 4 pieces – demonstrates ammonia and amine molecules. - Yellow (S, 17 mm): 2 pieces – used for sulfate and hydrogen sulfide models. 2. Connecting Bonds - Single Bonds: Off-white rods (27 mm), 20 pieces – rigid connections, simulate σ bonds (e.g., C–H, C–O). - Double Bonds: Gray spring rods (43 mm), 10 pieces – flexible design, demonstrate π bonds (e.g., C=O, C=C). - Lone Pair Orbitals: Colored vanes (red, green, blue), 10 pieces – simulate the spatial occupation of electron pairs (e.g., the lone pair in NH3). 3. Auxiliary Accessories - Base: Transparent plastic stand – used to secure molecular models (e.g., displaying the tetrahedral geometry of CH4). - Instruction Manual: Includes diagrams of the 14 VSEPR geometries (e.g., linear, trigonal pyramidal, octahedral) and assembly steps. Dimensions: 24 × 16.7 × 7 cm; Weight: 618 g

Core Functions:

1. Demonstration of 14 VSEPR Geometries - Linear (AX2): e.g., CO2 – central gray atom + two red ligand atoms, bond angle 180°. - Trigonal Pyramidal (AX3E): e.g., NH3 – central blue atom + three white ligand atoms + one lone pair orbital vane, bond angle ≈107°. - Tetrahedral (AX4): e.g., CH4 – central gray atom + four white ligand atoms, bond angle 109.5°. - Octahedral (AX6): e.g., SF6 – central yellow atom + six green ligand atoms, bond angle 90°. 2. Illustration of Electron Pair Repulsion Principles By inserting lone pair orbital vanes, the model visually demonstrates the repulsion order: lone pair–lone pair > lone pair–bonding pair > bonding pair–bonding pair, explaining bond angle variations (e.g., H2O bond angle 104.5° < CH4 bond angle 109.5°). 3. Molecular Polarity Analysis Compare models of CO2 (linear, nonpolar) and H2O (bent, polar) to understand the relationship between molecular symmetry and polarity.

Assembly Steps

1. Determine the molecular type: Identify the VSEPR geometry of the target molecule (e.g., PCl5 – trigonal bipyramidal, AX5). 2. Select the central atom: Choose a gray sphere as the central atom (e.g., P), and select ligand atoms (e.g., green for Cl). 3. Connect bonding electron pairs: Use five off-white single bonds to connect the central atom to the five green ligand atoms, forming a trigonal bipyramidal structure (axial bond angle 180°, equatorial bond angle 120°). 4. Add lone pairs (if applicable): For molecules like NH3, insert one blue lone pair orbital vane into the central atom and adjust ligand atom positions to form a trigonal pyramidal shape.

Product Features

Can simulate lone electron pairs: Ordinary ball-and-stick models can only show atoms. This kit is specially equipped with lone pair components, making it a dedicated teaching aid for VSEPR instruction; Intuitively reflects repulsion effects: Students can directly see lone electron pairs squeezing bonding electron pairs, causing bond angles to decrease, and understand valence shell electron pair repulsion theory; Compartmentalized storage box: Atom spheres, connecting rods, and lone pair components are stored in separate compartments for easy storage and counting; Components are highly versatile and can simultaneously build three-dimensional structures of organic and inorganic molecules. One set covers both molecular configuration and VSEPR theory teaching.

Teaching Uses

Classroom demonstration: Distinguishing electron pair spatial geometry from molecular spatial configuration; Student hands-on experiments, understanding lone electron pairs, bond angles, and valence shell electron pair repulsion; High school chemistry structure of matter elective topic teaching, college inorganic chemistry introduction.