Problem 97 - Chemistry The Central Science In Si Units

Question

Which of the following statements about hybrid orbitals is or are true? (i) After an atom undergoes sp hybridization, there is one unhybridized \(p\) orbital on the atom, (ii) Under \(s p^{2}\) hybridization, the large lobes point to the vertices of an equilateral triangle, and (iii) The angle between the large lobes of \(s p^{3}\) hybrids is \(109.5^{\circ}\).

Step-by-Step Solution

Answer

All statements (i), (ii), and (iii) are true about hybrid orbitals.

Step 1: Understanding sp Hybridization

In sp hybridization, one s orbital mixes with one p orbital to form two equivalent sp hybrid orbitals. This leaves two p} orbitals unhybridized. However, only one p orbital not participating in the hybridization becomes unhybridized. Therefore, statement (i) is true.

Step 2: Exploring sp² Hybridization

In sp² hybridization, one s orbital mixes with two p orbitals to form three equivalent sp² hybrid orbitals. These hybrid orbitals arrange themselves in a planar, triangular configuration. The large lobes point towards the vertices of an equilateral triangle, since each bond angle is 120°. Thus, statement (ii) is true.

Step 3: Analyzing sp³ Hybridization

For sp³ hybridization, one s orbital and three p orbitals hybridize to form four equivalent sp³ hybrid orbitals. The arrangement is tetrahedral, with bond angles of approximately 109.5° between the large lobes. Therefore, statement (iii) is true as well.

Step 4: Final Step: Conclusion

All provided statements (i), (ii), and (iii) accurately describe the respective hybridization scenarios and orbital arrangements. Hence, all three statements are true.

Key Concepts

Understanding sp Hybridization

Sp hybridization occurs when one s orbital combines with one p orbital. This creates two equivalent sp hybrid orbitals. These orbitals have a linear geometry and are oriented at 180° in relation to each other.

In this process, although two p orbitals are originally unhybridized, only one remains completely unhybridized after the hybridization occurs. This leaves us with a configuration in which one of the p orbitals is unchanged, thus allowing for characteristics of linear compounds such as acetylene (C₂H₂).

Some important features of sp hybridization include:

• Formation of linear molecules.
• 180° bond angles.
• One unhybridized p orbital remains, which can participate in π-bonding.

Grasping the concept of sp hybridization helps us understand molecular geometry, and the linear shape is a key indicator of sp hybrid presence.

Exploring sp² Hybridization

The sp² hybridization occurs when one s orbital combines with two p orbitals, forming three equivalent sp² hybrid orbitals. These orbitals adopt a trigonal planar arrangement.

The orientation of these hybrid orbitals leads to bond angles of 120°, with the large lobes pointing towards the vertices of an equilateral triangle. This is a common arrangement in molecules like ethylene (C₂H₄).

Key characteristics of sp² hybridization:

• Trigonal planar geometry.
• 120° bond angles.
• One unhybridized p orbital remains, which can engage in π-bonding, allowing for double bonds.

This type of hybridization helps us envision molecular structures where atoms are arranged in a planar configuration, offering a deeper understanding of how molecules such as benzene achieve their stable forms.

Analyzing sp³ Hybridization

Sp³ hybridization involves the combination of one s orbital with three p orbitals to create four equivalent sp³ hybrid orbitals. These orbitals take on a tetrahedral geometry, forming bond angles of approximately 109.5°.

This configuration allows molecules like methane (CH₄) to adopt their typical tetrahedral shapes, which is crucial for understanding saturated hydrocarbon structures.

Characteristics of sp³ hybridization include:

• Tetrahedral geometry.
• 109.5° bond angles, providing uniform spatial distribution of electron pairs.
• No unhybridized p orbitals remain, leading to single σ-bond formations.

By recognizing sp³ hybridization, you gain insight into the spatial arrangement and bonding characteristics that define a wide array of molecular structures seen in organic chemistry.