Bond Angle Deviation in Water

What is the primary reason for the deviation of the bond angle in water from the ideal tetrahedral angle of 109.5 degrees?

Which factor significantly contributes to the smaller bond angle of water (104.5 degrees) compared to the ideal tetrahedral angle (109.5 degrees)?

If the lone pairs on the oxygen atom in water had the same repulsive force as the bonding pairs, what would be the expected bond angle?

What is the relationship between the repulsion among electron pairs and the bond angle in a molecule?

Why does the concept of hybridization explain the difference in bond angles between an ideal tetrahedral molecule and water?

Electron Pair Geometry

Reasons for the Bond Angle Deviation in Water

Water (H₂O) molecule has a bent or V-shaped structure.
The ideal bond angle for sp³ hybridization is 109.5 degrees.
In water, the bond angle is 104.5 degrees.

Explanation of Deviation

The central oxygen atom in water has two bonded hydrogen atoms and two lone pairs of electrons.
These lone pairs are negatively charged and repel each other strongly due to their close proximity in space.
The presence of lone pairs exerts more repulsive force than bonding pairs.
This stronger repulsion between lone pairs forces the bonded hydrogen atoms closer together to minimize the repulsion.
Consequently, the bond angle reduces from the ideal tetrahedral bond angle of 109.5 degrees to 104.5 degrees in water.

Summary of Factors Influencing Bond Angle

Electron-pair Repulsion: Lone pairs exert more repulsion than bonding pairs.
Bond angles: The greater the repulsion among electron pairs (whether bonding or lone pairs), the smaller the bond angle.
Geometry: The electron pairs (lone pairs and bonded pairs) arrange themselves in a way to minimize repulsion, resulting in a specific molecular geometry.
Hybridization: The concept of hybridization explains the different kinds of molecular shapes, like the tetrahedral arrangement in water's case.
Repulsion: The repulsion between lone pairs and bonded pairs leads to a distorted shape, ultimately determining the observed bond angle.

This quiz explores the reasons for the bond angle deviation in water (H₂O), focusing on its bent structure and the influence of lone pairs of electrons. Learn how the bond angle in water reduces from the ideal 109.5 degrees to 104.5 degrees due to electron pair repulsion. Test your understanding of molecular geometry and electron interactions.