a. Methane (CH4) and the perchlorate ion (ClO4−) are both described as tetrahedral. What does this indicate about their bond angles?

Key Concepts

Tetrahedral Geometry

Tetrahedral geometry occurs when a central atom is bonded to four other atoms, resulting in a three-dimensional shape. In this arrangement, the bond angles are approximately 109.5 degrees, which minimizes electron pair repulsion according to VSEPR (Valence Shell Electron Pair Repulsion) theory. This geometry is characteristic of molecules like methane (CH4) and the perchlorate ion (ClO4−).

Bond Angles

Bond angles are the angles formed between adjacent bonds in a molecule. In tetrahedral molecules, the ideal bond angle is about 109.5 degrees due to the spatial arrangement of the electron pairs around the central atom. Deviations from this angle can occur due to factors such as lone pairs or differences in electronegativity among bonded atoms.

VSEPR Theory

VSEPR theory is a model used to predict the geometry of molecules based on the repulsion between electron pairs surrounding a central atom. It posits that electron pairs will arrange themselves to be as far apart as possible, leading to specific molecular shapes, such as tetrahedral for molecules with four bonding pairs. This theory helps explain the bond angles observed in molecules like CH4 and ClO4−.