The predicted bond angle in a water molecule H2O is approximately 104.5 degrees. This is different from the predicted bond angle in a carbon dioxide molecule CO2 , which is 180 degrees.The difference in bond angles can be explained by the molecular geometry and the presence of lone electron pairs. In a water molecule, the central atom is oxygen, which has two lone pairs of electrons and two bonding pairs with the two hydrogen atoms . According to the VSEPR Valence Shell Electron Pair Repulsion theory, the electron pairs around the central atom repel each other and arrange themselves to minimize repulsion. In the case of water, the molecular geometry is bent or V-shaped, and the lone pairs push the bonding pairs closer together, resulting in a bond angle of 104.5 degrees.On the other hand, in a carbon dioxide molecule, the central atom is carbon, which has no lone pairs of electrons and forms double bonds with two oxygen atoms. The molecular geometry of CO2 is linear, with the oxygen atoms on opposite sides of the carbon atom. In this arrangement, the electron pairs are as far apart as possible, leading to a bond angle of 180 degrees.