CLASS 8 · LEARNING KNOWLEDGE

Molecular geometry and simple models – basic principles

How it works

Molecular geometry describes the spatial arrangement of the atoms in a molecule. It is determined by electron pair repulsion (VSEPR model): electron pairs repel one another and arrange themselves as far away from each other as possible. This influences the shape of the molecule (e.g. linear, bent, tetrahedral). Models such as the ball-and-stick model and the space-filling model help to visualize molecular structures. The geometry has effects on properties such as polarity and reactivity.

Note
The spatial structure of a molecule results from the number of bonding partners and lone pairs on the central atom; electron pairs arrange themselves so that they are at a maximum distance from one another (VSEPR model).

An example

Which model is particularly suitable for clearly showing the spatial arrangement of the atoms in a water molecule?

The ball-and-stick model is well suited, as it clearly shows the angles between the atoms and the spatial structure. The spheres represent the atoms, the sticks the bonds.

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50 Exercises

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Own explanation and own practice exercises by AmyMath. Subject reference framework: Chemistry. The topic assignment may vary by federal state.