Further molecular geometry

This post will recap molecular geometry as required for Level 2, then look at molecular geometry relevant to Level 3 chemistry.

Molecular geometry review

Molecular geometry shows the bond angles between atoms in a molecule and the shape that is determined by the bond angles

These shapes are only given names for the actual atoms that are bonded to the central atom, and do not include any non-bonding electrons which may be 'attached' to the central atom

Electron geometry gives the angles, and names of the resultant shapes, due to the electron areas around a central atom

The first step in naming molecular shapes is to determine electron areas, and whether they are bonding or non bonding, using Lewis structures

Shapes and geometry are due to the electron -electron repulsion, leading to maximum charge separation and the lowest possible energy state. The theory that postulates this is called the Valence Shell Pair Repulsion theory, or VSEPR for short

Once a Lewis structure is completed molecular shapes are easily determined

Having a molecular shape and name then allows for prediction of molecular polarity

molecular shapes review

In all the simulations of molecular shapes below the light brown elongated lobes are nonbonding electrons.

Number of electron areas around central atom: 2

LINEAR MOLECULE

TRIGONAL PLANAR

BENT MOLECULES, #1

Number of electron areas around central atom: 4

TETRAHEDRAL MOLECULEs

TRIGONAL PYRAMIDAL MOLECULES

BENT MOLECULES #2

Number of electron areas around central atom: 5

TRIGONAL BIPYRAMIDAL MOLECULES

SEESAW MOLECULES

T SHAPED MOLECULES

Number of electron areas around central atom: 6

OCTAHEDRAL MOLECULES

SQUARE PYRAMIDAL MOLECULES

SQUARE PLANAR MOLECULES