Chapter 9: Problem 82
Draw the Lewis structure for the \(\mathrm{BeCl}_{4}^{2-}\) ion. Predict its geometry, and describe the hybridization state of the Be atom.
Short Answer
Expert verified
The Lewis structure has tetrahedral geometry with Be as sp³ hybridized.
Step by step solution
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Valence Electrons
Understanding valence electrons is essential to drawing Lewis structures. Valence electrons are the outermost electrons of an atom. They play a key role in bonding and chemical reactions. For \( \text{BeCl}_4^{2-} \), the total number of valence electrons contributes to forming its structure.
- Beryllium (Be): has 2 valence electrons.
- Chlorine (Cl): each has 7 valence electrons, and there are 4 Cl atoms contributing a total of 28 electrons.
- The 2- charge adds 2 more electrons to the count.
VSEPR Theory
VSEPR theory, which stands for Valence Shell Electron Pair Repulsion theory, predicts the shape of molecules. It is based on the idea that electron pairs around an atom in a molecule will space themselves as far apart as possible to minimize repulsion. This information helps us predict geometric arrangements of atoms in molecules.
In the case of \( \text{BeCl}_4^{2-} \), VSEPR theory is used to determine the 3D geometry based on the number of bonding pairs and lone pairs. Here, the Beryllium (Be) is surrounded by 4 chloride atoms. All 4 pairs of electrons are involved in bonding (as single bonds with chlorine), and there are no lone pairs on the central Be atom.
This arrangement naturally forms a tetrahedral shape because it achieves the maximal distance between all electron pairs, minimizing electron repulsion, which is a hallmark prediction of VSEPR. Understanding this theory as an organizing principle can be very powerful for solving chemistry problems related to molecular shape.
In the case of \( \text{BeCl}_4^{2-} \), VSEPR theory is used to determine the 3D geometry based on the number of bonding pairs and lone pairs. Here, the Beryllium (Be) is surrounded by 4 chloride atoms. All 4 pairs of electrons are involved in bonding (as single bonds with chlorine), and there are no lone pairs on the central Be atom.
This arrangement naturally forms a tetrahedral shape because it achieves the maximal distance between all electron pairs, minimizing electron repulsion, which is a hallmark prediction of VSEPR. Understanding this theory as an organizing principle can be very powerful for solving chemistry problems related to molecular shape.
Tetrahedral Geometry
Tetrahedral geometry is one of the common molecular shapes that result from a central atom with four bonds and no lone pairs of electrons around it. The shape is characterized by bond angles of about 109.5°.
For \( \text{BeCl}_4^{2-} \), the beryllium atom sits at the center, while the four chlorine atoms are positioned at the corners of the tetrahedron. This shape results from equal spacing between atoms to minimize electron pair repulsion according to VSEPR theory.
A tetrahedral geometry is highly symmetric and can be found in many compounds, not just ions like \(\text{BeCl}_4^{2-}\). Recognizing this shape allows chemists to predict physical and chemical properties of the compound, such as bond angles and the spatial arrangement of atoms.
For \( \text{BeCl}_4^{2-} \), the beryllium atom sits at the center, while the four chlorine atoms are positioned at the corners of the tetrahedron. This shape results from equal spacing between atoms to minimize electron pair repulsion according to VSEPR theory.
A tetrahedral geometry is highly symmetric and can be found in many compounds, not just ions like \(\text{BeCl}_4^{2-}\). Recognizing this shape allows chemists to predict physical and chemical properties of the compound, such as bond angles and the spatial arrangement of atoms.
Hybridization
Hybridization is the concept of mixing atomic orbitals into new hybrid orbitals suitable for the pairing of electrons to form chemical bonds. In essence, it helps explain molecular shapes from a quantum mechanical view.
For \( \text{BeCl}_4^{2-} \), beryllium is the central atom and is associated with sp³ hybridization. This hybridization occurs because one s orbital and three p orbitals from beryllium blend to form four equivalent hybrid orbitals. These sp³ hybrid orbitals then overlap with orbitals from chlorine to form \( \sigma \) bonds.
The sp³ hybridization is consistent with the tetrahedral geometry, where the bond angles are approximately 109.5°. Understanding hybridization provides insight into the electron distribution in atoms and its effect on the angle and strength of bonds. As such, it is a crucial concept for understanding the basis of molecular geometry in more complex molecules.
For \( \text{BeCl}_4^{2-} \), beryllium is the central atom and is associated with sp³ hybridization. This hybridization occurs because one s orbital and three p orbitals from beryllium blend to form four equivalent hybrid orbitals. These sp³ hybrid orbitals then overlap with orbitals from chlorine to form \( \sigma \) bonds.
The sp³ hybridization is consistent with the tetrahedral geometry, where the bond angles are approximately 109.5°. Understanding hybridization provides insight into the electron distribution in atoms and its effect on the angle and strength of bonds. As such, it is a crucial concept for understanding the basis of molecular geometry in more complex molecules.
