VSEPR Theory Quiz and Flashcards for Students

Questions and Answers

What does the acronym VSEPR stand for?

Valence-shell electron-pair repulsion theory

What is the VSEPR Model used for?

To explain the 3-dimensional shape of molecules

What does VSEPR Theory state about molecular shapes?

The repulsion between electron pairs causes molecular shapes to adjust so that the valence-electron pairs stay as far away as possible.

What is an unshared pair?

Strongly repels the bonding pairs, pushing them together. Signup and view all the answers

Describe a linear pair in terms of molecular geometry.

Drawn in a straight line, angle 180, one central, 2 peripheral electrons. Signup and view all the answers

What is a Trigonal Planar arrangement?

One central and 3 peripheral atoms on a plane, angle 120. Signup and view all the answers

What characterizes a Tetrahedral arrangement?

One central and 4 peripheral atoms, angle 109.5. Signup and view all the answers

What happens in a Tetrahedral arrangement with 1 pair of unshared electrons?

One central, 4 peripheral, 1 pair unshared electrons; forms trigonal pyramidal with angle 107. Signup and view all the answers

How does a Tetrahedral arrangement with 2 pairs of unshared electrons differ?

One central, 4 peripheral, 2 pairs unshared electrons; known as a bent angle 104.5. Signup and view all the answers

What defines a Trigonal Bipyramidal arrangement?

One central, 5 peripheral; angles are 120 on the plane & 90 vertical. Signup and view all the answers

Study Notes

VSEPR Theory Overview

VSEPR stands for valence-shell electron-pair repulsion theory.
The theory describes how the arrangement of electron pairs around a central atom determines the shape of a molecule.

VSEPR Model

The model provides a framework for predicting the three-dimensional structure of molecules based on electron pair repulsion.

Molecular Shape Determination

VSEPR theory emphasizes that electron pairs (bonding and lone pairs) repel each other, leading to the arrangement that maximizes their distance from each other.

Unshared Pairs

Unshared (lone) electron pairs exert stronger repulsion than bonded pairs, influencing molecular geometry significantly by pushing bonding pairs closer together.

Linear Geometry

A linear molecular shape consists of a central atom with two peripheral atoms, forming a straight line with a bond angle of 180 degrees.

Trigonal Planar Geometry

In a trigonal planar arrangement, one central atom is bonded to three peripheral atoms, arranged in a plane with a bond angle of 120 degrees.

Tetrahedral Geometry

A tetrahedral shape features one central atom bonded to four peripheral atoms, with a bond angle of 109.5 degrees.

Trigonal Pyramidal Geometry

A trigonal pyramidal shape occurs when one of the four pairs of electrons in a tetrahedral arrangement is a lone pair. This causes the angle between the peripheral atoms to be about 107 degrees.

Bent Geometry

In cases with two lone pairs, the shape becomes bent with a bond angle of approximately 104.5 degrees, derived from a tetrahedral structure.

Trigonal Bipyramidal Geometry

A trigonal bipyramidal arrangement consists of a central atom bonded to five peripheral atoms, with bond angles of 120 degrees in the equatorial plane and 90 degrees in the axial positions.

Description

Test your understanding of VSEPR theory with these flashcards. Each card provides key definitions and concepts related to valence-shell electron-pair repulsion theory and molecular shapes. Perfect for students studying chemistry!