Question

4 electron pairs give you what molecular geometry and angles?

A) Linear, 180°
B) Trigonal Planar, 120°
C) Tetrahedral, 109.5°
D) Trigonal Bipyramidal, 120° and 90°

Answer 1

Four electron pairs around a central atom produce a tetrahedral geometry with an ideal bond angle of 109.5 degrees; however, the presence of lone pairs can slightly alter these angles.

Step-by-step explanation:

The molecular geometry formed by four electron pairs is a tetrahedral shape. This arrangement of electron pairs results in bond angles that are approximately 109.5°. However, when referring to the resulting molecular structure with lone pairs, the angles can be slightly different. For a molecule with four bonding electron pairs (no lone pairs), the geometry is tetrahedral and has bond angles of 109.5°. If there are lone pairs, the bond angles might be slightly less than 109.5°, depending on the arrangement of the lone pairs and bonding pairs.

Answer 2

Four electron pairs around a central atom result in a tetrahedral electron-pair geometry with ideal bond angles of 109.5 degrees. If all pairs are bonding pairs, the molecular geometry is also tetrahedral. The correct answer is C) Tetrahedral, 109.5° (option C).

Step-by-step explanation:

When a molecule has four electron pairs, these pairs are typically arranged in a way to minimize repulsion between them. According to VSEPR (Valence Shell Electron Pair Repulsion) theory, four regions of electron density around a central atom will be positioned as far apart from each other as possible. This arrangement is called the tetrahedral electron-pair geometry. The ideal angle between the electron pairs in a perfect tetrahedral geometry is approximately 109.5 degrees.

The molecular geometry is also determined by the number of bonding pairs and lone pairs in the structure. If all four pairs are bonding pairs, the molecular structure is tetrahedral and the angles between the bonds are 109.5°. However, the presence of lone pairs alters the molecular structure and can reduce the bond angle from the ideal tetrahedral angle. For example, if there is one lone pair, the molecular structure is trigonal pyramidal, and if there are two lone pairs, the molecular structure is bent, which decreases the bond angles slightly.

Thus, the correct answer to '4 electron pairs give you what molecular geometry and angles?' is C) Tetrahedral, 109.5°.