what are the angles a and b in the actual molecule of which this is a lewis structure? note for advanced…

what are the angles a and b in the actual molecule of which this is a lewis structure? note for advanced students: give the ideal angles, and dont worry about small differences from the ideal that might be caused by the fact that different electron groups may have slightly different sizes.

what are the angles a and b in the actual molecule of which this is a lewis structure? note for advanced students: give the ideal angles, and dont worry about small differences from the ideal that might be caused by the fact that different electron groups may have slightly different sizes.

Answer

Explanation:

Step1: Identify the molecular geometry

The molecule shown is water ($H_2O$). It has a bent molecular geometry with an oxygen - centered atom having two bonding pairs and two lone pairs of electrons.

Step2: Recall the ideal bond - angle for bent geometry

For a bent molecule with a central atom having two bonding pairs and two lone pairs, the ideal bond - angle is based on the tetrahedral electron - pair geometry. In a tetrahedral arrangement, the bond - angle is 109.5°. But due to the repulsion of the two lone pairs on the oxygen atom in water, the bond - angle is reduced. However, for the ideal case (ignoring the effects of lone - pair repulsion), the angle 'a' and 'b' in a tetrahedral - based bent structure are 109.5°.

Answer:

a = 109.5° b = 109.5°