Shapes of simple molecules and ions (3.1.3.5)

What do the dashes and wedges mean in molecule shapes?

Dashes - bond going into paper

Wedges - bond coming out of paper

What is the shape and bond angles of a molecule with 2 bonding pairs?

Shape - linear 

Bond angles - 180°

What is the shape and bond angles of a molecule with 3 bonding pairs?

Shape - trigonal planar

Bond angles - 120°

What is the shape and bond angles of a molecule with 2 bonding pairs and 1 lone pair?

Shape - bent (v-shape)

Bond angles - 118°

What is the shape and bond angles of a molecule with 4 bonding pairs?

Shape - tetrahedral

Bond angles - 109.5°

What is the shape and bond angles of a molecule with 3 bonding pairs and 1 lone pair?

Shape - trigonal pyramidal

Bond angles - 107°

What is the shape and bond angles of a molecule with 2 bonding pairs and 2 lone pairs?

Shape - bent (v-shape)

Bond angles - 104.5°

What is the shape and bond angles of a molecule with 5 bonding pairs?

Shape - trigonal bipyramidal

Bond angles - 90° and 120°

What is the shape and bond angles of a molecule with 6 bonding pairs?

Shape - octahedral

Bond angles - 90°

What is the shape and bond angles of a molecule with 4 bonding pairs and 2 lone pairs?

Shape - square planar

Bond angles - 90°

Why do molecules take these shapes?

Molecules take these shapes to minimise electron-electron repulsion

Lone pairs repel more than bonding pairs so it increases the bond angle when lone pairs are present

Bonding pairs repel equally