The angle between the bonding orbitals of a molecules `AX_(3)` with zero dipole moment is

Options

A. `120^(º)`
B. `109^(º)`
C. `104^(º)`
D. `180^(º)`

Answer

To determine the angle between the bonding orbitals of a molecule of the type AX₃ with zero dipole moment, we can follow these steps:

### Step 1: Understand the Molecular Geometry
- The molecule AX₃ consists of one central atom A and three surrounding atoms X.
- The presence of three identical surrounding atoms suggests a symmetrical arrangement.

**Hint:** Consider the arrangement of atoms around the central atom to determine the molecular geometry.

### Step 2: Identify the Molecular Shape
- For a molecule with the formula AX₃, the molecular geometry is typically trigonal planar if there are no lone pairs on the central atom A.
- A trigonal planar arrangement has the three atoms X positioned at the corners of an equilateral triangle.

**Hint:** Recall the VSEPR theory, which helps predict the shape of molecules based on the number of bonding and lone pairs.

### Step 3: Determine the Bond Angles
- In a trigonal planar geometry, the bond angles between the surrounding atoms (X) are equal.
- The ideal bond angle in a trigonal planar arrangement is 120 degrees.

**Hint:** Visualize or sketch the trigonal planar structure to see how the atoms are arranged and the angles formed.

### Step 4: Consider the Dipole Moment
- A zero dipole moment indicates that the molecule is non-polar. This occurs when the individual bond dipoles cancel each other out.
- In the case of AX₃, if A is less electronegative than X (like in BF₃), the bond dipoles will cancel due to symmetry.

**Hint:** Think about how the symmetry of the molecule affects the overall dipole moment.

### Conclusion
- Therefore, the angle between the bonding orbitals of a molecule AX₃ with zero dipole moment is **120 degrees**.

**Final Answer:** 120 degrees