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Questions and Answers
Hydrogen gas (H2) forms a $ ext{σ}$ bond due to the overlapping of two 1s orbitals.
Hydrogen gas (H2) forms a $ ext{σ}$ bond due to the overlapping of two 1s orbitals.
True
Carbon in its ground state can form four bonds due to having four half-filled 2p orbitals.
Carbon in its ground state can form four bonds due to having four half-filled 2p orbitals.
False
The promotion of a 2s electron to a higher energy 2p orbital allows carbon to form four equivalent C–H bonds.
The promotion of a 2s electron to a higher energy 2p orbital allows carbon to form four equivalent C–H bonds.
True
The sp3 hybrid orbitals are formed from the hybridization of 2s and two 2p orbitals in carbon.
The sp3 hybrid orbitals are formed from the hybridization of 2s and two 2p orbitals in carbon.
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In the promoted state, carbon has a configuration of [He]2s12px12py12pz0.
In the promoted state, carbon has a configuration of [He]2s12px12py12pz0.
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Hybrid orbitals point towards the vertices of a tetrahedron in the sp3 hybridization of carbon.
Hybrid orbitals point towards the vertices of a tetrahedron in the sp3 hybridization of carbon.
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The overlapping of four 1s H orbitals with the promoted C atom results in the formation of two different $ ext{σ}$ bonds.
The overlapping of four 1s H orbitals with the promoted C atom results in the formation of two different $ ext{σ}$ bonds.
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Hydrogen atoms in H2 have a higher energy state due to their bonding configuration.
Hydrogen atoms in H2 have a higher energy state due to their bonding configuration.
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The process of promoting a 2s electron to a 2p orbital in carbon requires a significant amount of energy due to high electron repulsion.
The process of promoting a 2s electron to a 2p orbital in carbon requires a significant amount of energy due to high electron repulsion.
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The electron pair in H2 occupies separate orbitals, leading to the formation of a bonding orbital.
The electron pair in H2 occupies separate orbitals, leading to the formation of a bonding orbital.
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In sp3 hybridization, a carbon atom has 25% p-orbital character.
In sp3 hybridization, a carbon atom has 25% p-orbital character.
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Methane (CH4) is described as having a tetrahedral molecular geometry.
Methane (CH4) is described as having a tetrahedral molecular geometry.
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The hybridization of nitrogen in ammonia (NH3) is sp2.
The hybridization of nitrogen in ammonia (NH3) is sp2.
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PCl5 exhibits sp3 hybridisation.
PCl5 exhibits sp3 hybridisation.
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Oxygen in water (H2O) exhibits a bent molecular shape due to sp3 hybridization.
Oxygen in water (H2O) exhibits a bent molecular shape due to sp3 hybridization.
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In ethene (C2H4), each carbon atom is sp2 hybridised.
In ethene (C2H4), each carbon atom is sp2 hybridised.
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In nitrogen's sp3 hybridized state, it has one unpaired electron.
In nitrogen's sp3 hybridized state, it has one unpaired electron.
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Diborane (B2H6) has 10 valence electrons.
Diborane (B2H6) has 10 valence electrons.
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The hybridization state of carbon changes from p to s when bonding occurs.
The hybridization state of carbon changes from p to s when bonding occurs.
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The sp hybrid orbital consists of 100% p-orbital character.
The sp hybrid orbital consists of 100% p-orbital character.
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In the hybridization of oxygen, there are two lone pairs of electrons.
In the hybridization of oxygen, there are two lone pairs of electrons.
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In a tetrahedral molecule, the hybridisation state is typically sp2.
In a tetrahedral molecule, the hybridisation state is typically sp2.
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The bond angle in methane is approximately 109.5 degrees.
The bond angle in methane is approximately 109.5 degrees.
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The molecular geometry of ammonia (NH3) is linear.
The molecular geometry of ammonia (NH3) is linear.
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In sp2 hybridisation, there is one unhybridised p-orbital per atom.
In sp2 hybridisation, there is one unhybridised p-orbital per atom.
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In sp3 hybridization, each hybrid orbital can accommodate only one electron.
In sp3 hybridization, each hybrid orbital can accommodate only one electron.
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Ethyne (C2H2) exhibits trigonal planar geometry.
Ethyne (C2H2) exhibits trigonal planar geometry.
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The molecular formula for aspirin is C9H8O4.
The molecular formula for aspirin is C9H8O4.
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The hybrid orbitals in trigonal bipyramidal molecules require d-orbitals.
The hybrid orbitals in trigonal bipyramidal molecules require d-orbitals.
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Each sp3 hybridised carbon atom in a molecule retains one unhybridised p-orbital.
Each sp3 hybridised carbon atom in a molecule retains one unhybridised p-orbital.
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Study Notes
H2 – σ Bond
- Hydrogen atoms have one 1s electron in a spherical orbital.
- In H2, the shared 1s electrons occupy a single orbital that encompasses both atoms, forming a sausage shape distribution.
- This orbital overlap results in a sigma (σ) bond.
Hybridisation – the C-Atom
- A carbon atom in its ground state has an electron configuration of [He]2s22px12py12pz0, suggesting the ability to form only two bonds due to two half-filled p orbitals.
- Promotion elevates a 2s electron to a higher-energy 2p orbital, resulting in the promoted state: [He]2s12px12py12pz1. This allows for the formation of four bonds, as the energy investment is recovered through bond formation.
- The energy required for promotion is minimal as the electron experiences limited repulsion in the empty 2p orbital.
- However, overlapping four 1s orbitals from hydrogen with the promoted carbon atom would yield sigma bonds of varying energy and length, contradicting the experimentally observed equivalence of the four C-H bonds in methane.
Hybridisation – sp3
- To address the inconsistency in bond equivalence, the 2s and three 2p orbitals of the promoted carbon atom hybridise.
- This hybridisation produces four identical sp3 hybrid orbitals with a tetrahedral spatial arrangement.
- Each sp3 hybrid orbital comprises a 75% p-orbital and 25% s-orbital character.
- The formation of four equivalent C-H bonds in methane highlights the tetrahedral geometry of the sp3 hybridization.
Hybridisation – sp3 : Nitrogen
- Applying the same principle to nitrogen, the hybridization of its orbitals leads to four sp3 hybrid orbitals, with one lone pair residing in one of the sp3 orbitals.
- The geometry of ammonia (NH3) with three bond pairs and one lone pair is trigonal pyramidal, dictated by the sp3 hybridization.
Hybridisation – sp3 : Oxygen
- Oxygen, like nitrogen, undergoes sp3 hybridization, resulting in four sp3 orbitals. In water (H2O), two lone pairs occupy two of the sp3 orbitals.
- The resulting angular or bent shape of water arises from the two bond pairs and two lone pairs arranged in an AB2E2 pattern around the central oxygen atom.
Hybridisation - Summary
- The hybridisation of atomic orbitals affects the geometry and properties of molecules.
- Depending on the number of orbitals involved, different hybridisation types emerge with unique spatial orientations and bond characteristics.
Hybridisation – sp2
- Ethene (CH2=CH2) exhibits trigonal planar geometry around each carbon atom.
- The molecule is planar overall.
- Each carbon atom adopts sp2 hybridization, with one unhybridised 2p orbital.
- The sp2 hybrid orbitals create sigma bonds, while the unhybridised p orbitals form pi bonds.
- The sp2 hybrid orbital is characterized by 67% p-orbital and 33% s-orbital character.
Hybridisation – sp2 – Aspirin
- Aspirin (acetylsalicylic acid), a common pain reliever, exhibits sp2 hybridization at specific atoms, including the carbon atoms in the carboxylic acid group and the acetyl group.
Hybridisation – sp
- In ethyne (CH≡CH), each carbon atom adopts a linear geometry.
- The molecule is linear overall.
- Each carbon atom undergoes sp hybridization, resulting in two unhybridised p orbitals.
- The sp hybrid orbitals form sigma bonds, and the unhybridised p orbitals form pi bonds.
- The sp hybrid orbital comprises 50% p-orbital and 50% s-orbital character.
Hybridisation – sp3, sp2, sp – Terbinafine
- Terbinafine, an antifungal medication, incorporates various hybridisations within its structure.
- The tertiary amine nitrogen exhibits sp3 hybridization, while the carbon atoms involved in alkenes (double bonds) are sp2 hybridised and the carbon atoms in alkynes (triple bonds) are sp hybridised.
Molecular Orbital Theory Exceptions
- Diborane (B2H6) exhibits a unique structure with a total of 12 valence electrons.
- Its structure deviates from typical hybridisation patterns, requiring detailed treatment using molecular orbital theory to understand its bonding.
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Description
This quiz covers the concepts of sigma bonds in H2 and the hybridisation of carbon atoms. It explores how the electron configurations influence bonding and the formation of molecular structures. Delve into the characteristics of orbital overlap and bond formation.
