Final answer:
The ideal bond angle for a tetrahedral compound is 109.5 degrees, as it minimizes electron-pair repulsion and corresponds to the spatial arrangement of atoms in the geometry of a perfect tetrahedron.
Step-by-step explanation:
For a tetrahedral compound, the ideal bond angle in degrees is option (C) 109.5. In a tetrahedral molecule, the central atom is bonded to four other atoms which are located at the corners of an imaginary tetrahedron. The electron-pair geometry of these molecules dictates that they adopt a tetrahedral spatial arrangement so as to minimize electron-pair repulsion, resulting in bond angles of approximately 109.5°. When there are lone pairs involved, such as in a trigonal pyramidal geometry, the bond angles might be slightly less due to increased lone pair-bond pair repulsions. However, the question specifies a tetrahedral compound, implying there are no lone pairs altering the bond angles.