Presentation is loading. Please wait.

Presentation is loading. Please wait.

Shapes of Molecules. Electron Pair Repulsions Electron pairs are negatively charged, they repel each other and therefore like to get as far apart as possible.

Published byBruno Rogers Modified over 8 years ago

Similar presentations

Presentation on theme: "Shapes of Molecules. Electron Pair Repulsions Electron pairs are negatively charged, they repel each other and therefore like to get as far apart as possible."— Presentation transcript:

1 Shapes of Molecules

2 Electron Pair Repulsions Electron pairs are negatively charged, they repel each other and therefore like to get as far apart as possible. Using molymod kits build a structure to represent methane (CH 4 ), what do you think is the angle between the bonding pairs?

3 Tetrahedral When there are 4 bonding pairs (BPs) of electrons around the central atom they adopt a ‘Tetrahedral’ shape. The bond angle is approximately 109 ◦ This is represented by:

4 Drawing 3D Structures »Represents a bond in the plane of the paper. »Represents a bond in a direction behind the plane of the paper. »Represents a bond in a direction in front of the plane of the paper.

5 What about lone pairs? Lone pairs also repel against the bonding pairs. In fact their repulsion is even stronger! Try making structures for Ammonia (NH 3 ) and Water (H 2 O) How would you describe the shapes and bond angles?

6 Water and Ammonia Ammonia’s 3 bonding pairs and lone pair adopt similar positions to 4 bonding pairs in methane. Bond Angle = ~109 ◦ Name = Pyramidal Water has 2 lone pairs and 2 boning pairs and again they adopt positions similar to methane. Bond Angle = ~109 ◦ Name = Bent

7 Linear Molecules When there are only two groups around the central atom they will get as far apart as possible. Name = Linear Bond Angle = 180 ◦ E.g. BeCl 2 and CO 2

8 Planar Molecules When there are three groups of electrons around the central atom the furthest they can get apart is 120 ◦ Name = Trigonal Planar Bond angle = 120 ◦ E.g. BF 3, methanal and ethene

9 Trigonal Bipyramidal Molecules This is where there are 5 groups of bonding electrons. It is like trigonal planar but with two extra groups of electrons occupying spaces above and below the plane. Name = Trigonal bipyramidal Bond angle = 120° or 90 ° E.g. PCl 5

10 Octahedral This is where 6 groups of bonding electrons surround a central atom, it is similar to trigonal bipyramidal apart from having an extra group of electrons in the central plane. Name = Octahedral Bond Angle = 90° E.g. SF 6

11 Shapes of ions You can use the same principles to determine the shapes of ions by looking at how many electrons have been gained or lost. E.g. NH 4 + AmmoniaNH 2 - TetrahedralPyramidalBent 4xBP 3xBP and 1xLP 2xBP and 2xLP

12 Now you try… Now have a go at 3.2 Problems 1-3 before attempting the ‘Balloon Challenge’.

Download ppt "Shapes of Molecules. Electron Pair Repulsions Electron pairs are negatively charged, they repel each other and therefore like to get as far apart as possible."

Similar presentations

VSPER Molecular shapes Valence Shell Electron Repulsion Theory.

VSPER Molecular shapes Valence Shell Electron Repulsion Theory.
1 Shapes of Molecules Determined by number of valence electrons of the central atom 3-D shape a result of bonded pairs and lone pairs of electrons Use.

1 Shapes of Molecules Determined by number of valence electrons of the central atom 3-D shape a result of bonded pairs and lone pairs of electrons Use.
Basic Chemistry Copyright © 2011 Pearson Education, Inc. 1 Chapter 10 Structures of Solids and Liquids 10.2 Shapes of Molecules and Ions (VSEPR Theory)

Basic Chemistry Copyright © 2011 Pearson Education, Inc. 1 Chapter 10 Structures of Solids and Liquids 10.2 Shapes of Molecules and Ions (VSEPR Theory)
1 Chapter 10 Molecular Structure: Solids and Liquids 10.3 Shapes of Molecules and Ions (VSEPR Theory) Copyright © 2008 by Pearson Education, Inc. Publishing.

1 Chapter 10 Molecular Structure: Solids and Liquids 10.3 Shapes of Molecules and Ions (VSEPR Theory) Copyright © 2008 by Pearson Education, Inc. Publishing.
Chapter 9 Molecular Geometry and Bonding Theories.

Chapter 9 Molecular Geometry and Bonding Theories.
Molecular Shapes Chapter 6 Section 3. Molecular Structure It mean the 3-D arrangement of atoms in a molecule Lewis dot structures show how atoms are bonded.

Molecular Shapes Chapter 6 Section 3. Molecular Structure It mean the 3-D arrangement of atoms in a molecule Lewis dot structures show how atoms are bonded.
Advanced Higher Chemistry Unit 1 Shapes of molecules and polyatomic ions.

Advanced Higher Chemistry Unit 1 Shapes of molecules and polyatomic ions.
Drawing Lewis Structures and VSEPR A Tutorial on Writing Lewis Dot Structure.

Drawing Lewis Structures and VSEPR A Tutorial on Writing Lewis Dot Structure.
Molecular Geometry (Shapes of Molecules)

Molecular Geometry (Shapes of Molecules)
Shapes of molecules & ions. VSEPR theory VSEPR - the Valence Shell Electron Pair Repulsion theory is used to obtain the shape of simple molecules and.

Shapes of molecules & ions. VSEPR theory VSEPR - the Valence Shell Electron Pair Repulsion theory is used to obtain the shape of simple molecules and.
VSEPR Theory Valence Shell Electron Pair Repulsion.

VSEPR Theory Valence Shell Electron Pair Repulsion.
Molecular Shape Section 9.4

Molecular Shape Section 9.4
Shapes of molecules 1) sketch the Lewis structure 2) locate the central atom 3) count regions of electron density around the central atom double/triple.

Shapes of molecules 1) sketch the Lewis structure 2) locate the central atom 3) count regions of electron density around the central atom double/triple.
Shapes of molecules. How to predict the shapes of molecules Shapes can be predicted from the number of electron pairs around the central atom of a molecule.

Shapes of molecules. How to predict the shapes of molecules Shapes can be predicted from the number of electron pairs around the central atom of a molecule.
Shapes of molecules  The shapes of molecules and ions can be described by valence shell electron pair repulsion  VSEPR predicts the shapes and bond.

Shapes of molecules  The shapes of molecules and ions can be described by valence shell electron pair repulsion  VSEPR predicts the shapes and bond.
IIIIII Molecular Geometry Molecular Structure. A. VSEPR Theory  Valence Shell Electron Pair Repulsion Theory  Electron pairs orient themselves so that.

IIIIII Molecular Geometry Molecular Structure. A. VSEPR Theory  Valence Shell Electron Pair Repulsion Theory  Electron pairs orient themselves so that.
Cornell Notes (Section 8.4, especially page 263  Topic: Molecular Geometry  Date: 2/7/2012  VSEPR = Valence Shell Electron Pair Repulsion  Valence.

Cornell Notes (Section 8.4, especially page 263  Topic: Molecular Geometry  Date: 2/7/2012  VSEPR = Valence Shell Electron Pair Repulsion  Valence.
Molecular Shapes If you were to draw the Lewis structure for Carbon tetrachloride based on what you have already taken in this class, you may come up with.

Molecular Shapes If you were to draw the Lewis structure for Carbon tetrachloride based on what you have already taken in this class, you may come up with.
Valence Shell Electron Pair Repulsion Theory (4.3 of textbook)

Valence Shell Electron Pair Repulsion Theory (4.3 of textbook)
VSEPR. This is the shape that CO 2 makes. 1. Linear 2. Bent 3. Trigonal planar 4. Tetrahedral 5. Trigonal pyramidal 6. Trigonal bipyramidal 7. See-saw.

VSEPR. This is the shape that CO 2 makes. 1. Linear 2. Bent 3. Trigonal planar 4. Tetrahedral 5. Trigonal pyramidal 6. Trigonal bipyramidal 7. See-saw.

Similar presentations

Ads by Google