Bond angles are determined by the electron pair repulsion around a central atom, as described by VSEPR theory.
The ideal bond angles are influenced by hybridization; for example, $sp^3$ hybridization has an ideal bond angle of 109.5°.
Bond angles can be affected by lone pairs of electrons, which typically decrease the bond angle between bonded atoms.
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.
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.