Bond angle

Definition

A bond angle is the geometric angle between two adjacent bonds in a molecule. It helps determine the overall shape of the molecule.

5 Must Know Facts For Your Next Test

1. Bond angles are determined by the electron pair repulsion around a central atom, as described by VSEPR theory.
2. The ideal bond angles are influenced by hybridization; for example, $sp^3$ hybridization has an ideal bond angle of 109.5°.
3. Bond angles can be affected by lone pairs of electrons, which typically decrease the bond angle between bonded atoms.
4. In a water molecule (H$_2$O), the bond angle is approximately 104.5°, which is less than the ideal tetrahedral angle due to lone pair repulsion.
5. Molecules with linear geometry have bond angles of 180°, such as carbon dioxide (CO$_2$).

Review Questions

• What determines the bond angle in a molecule?
• How does hybridization affect bond angles?
• Why is the bond angle in a water molecule less than the ideal tetrahedral angle?

Related terms

VSEPR Theory: Valence Shell Electron Pair Repulsion (VSEPR) theory predicts the geometry of molecules based on electron pair repulsions around a central atom.

$sp^3$ Hybridization: $sp^3$ hybridization occurs when one s orbital and three p orbitals mix to form four equivalent hybrid orbitals, resulting in a tetrahedral geometry with an ideal bond angle of 109.5°.

Lone Pair: A lone pair refers to a pair of valence electrons that are not shared with another atom and can influence molecular geometry and bond angles.