How do we predict bond angles and the shapes of molecules?

Using the VSEPR theory, the electron bond pairs and lone pairs on the center atom will help us predict the shape of a molecule. The shape of a molecule is determined by the location of the nuclei and its electrons. The electrons and the nuclei settle into positions that minimize repulsion and maximize attraction.

How do you compare bond lengths between two molecules?

Bond length is related to bond order: when more electrons participate in bond formation the bond is shorter. Bond length is also inversely related to bond strength and the bond dissociation energy: all other factors being equal, a stronger bond will be shorter.

How do you predict molecular geometry?

The valence shell electron-pair repulsion theory (abbreviated VSEPR) is commonly used to predict molecular geometry. The theory says that repulsion among the pairs of electrons on a central atom (whether bonding or non-bonding electron pairs) will control the geometry of the molecule.

How will you explain the bond angles of molecules with the help of electronegativity?

In VSEPR theory, electronegativity of atoms/groups will effect bond angles due to changes in the distribution of electron pairs around the central atom (and thus changes in severity of electron pair repulsion).

How do you compare bond strength?

Generally, as the bond strength increases, the bond length decreases. Thus, we find that triple bonds are stronger and shorter than double bonds between the same two atoms; likewise, double bonds are stronger and shorter than single bonds between the same two atoms.

What could cause the bond angles to differ between molecules?

Many factors lead to variations from the ideal bond angles of a molecular shape. Size of the atoms involved, presence of lone pairs, multiple bonds, large groups attached to the central atom, and the environment that the molecule is found in are all common factors to take into consideration.