What is the correct order of decreasing X-A-X bond angle in CF4, SCI2, and CS2 molecules?
The correct order of decreasing X-A-X bond angle is: CF4 > SCI2 > CS2. CF4 has the largest X-A-X bond angle among the three molecules due to its symmetrical tetrahedral shape, which results in 109.5° bond angles. SCI2 has a bent shape with two lone pairs on the central atom, leading to a slightly smaller bond angle of 103.7°. CS2 has a linear shape with 180° bond angles, making it the smallest of the three. The other options listed are incorrect as they do not follow the trend of decreasing bond angles.
Explanation:
CF4: In CF4, the central atom is carbon with four fluorine atoms surrounding it, creating a tetrahedral shape. This symmetrical arrangement of atoms results in a bond angle of 109.5°.
SCI2: In SCI2, the central atom is sulfur with two chlorine atoms and two lone pairs surrounding it. This leads to a bent shape with a bond angle of less than 109.5° due to the presence of lone pairs on the central atom.
CS2: In CS2, the central atom is sulfur with two carbon atoms surrounding it. This linear arrangement of atoms results in a bond angle of 180°, making it the molecule with the smallest X-A-X bond angle among the three.
Therefore, the correct order of decreasing X-A-X bond angle (largest to smallest) for CF4, SCI2, and CS2 is CF4 > CS2 > SCI2.