Domanda del libro di testo
Looking ahead in Chapter 3, we describe how the formal charge on an atom can be used to predict the number of lone pairs. Given the charge, or lack of charge, on each atom, fill in the electron pairs.
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Ch. 2 - General Chemistry Translated: Finding the Electrons
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471
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TOC.tableOfContents
- Ch. 2 - General Chemistry Translated: Finding the Electrons114
- Ch. 3 - Alkanes and Cycloalkanes: Properties and Conformational Analysis109
- Ch. 4 - Acids and Bases/Electron Flow144
- Ch. 5 - Chemical Reaction Analysis: Thermodynamics and Kinetics118
- Ch. 6 - Stereoisomerism: Arrangement of Atoms in Space112
- Ch. 7 - Principles of Green (Organic) Chemistry3
- Ch. 8 - Alkenes 1: Properties and Electrophilic Additions158
- Ch. 9 - Alkenes 2: Oxidation and Reduction150
- Ch. 10 - Alkynes: Electrophilic Addition and Redox Reactions101
- Ch. 11 - Properties and Synthesis of Alkyl Halides: Radical Reactions108
- Ch. 12 - Substitution and Elimination: Reactions of Haloalkanes172
- Ch. 13 - Alcohols, Ethers and Related Compounds: Substitution and Elimination239
- Ch. 14 - Structural Identification 1: Infrared Spectroscopy and Mass Spectrometry54
- Ch. 15 - Structural Identification 2: Nuclear Magnetic Resonance Spectroscopy93
- Ch. 16 - Metals in Organic Chemistry48
- Ch. 17 - Carbonyl Addition Reactions: Aldehydes and Ketones45
- Ch. 18 - Nucleophilic Acyl Substitution 1: Carboxylic Acids18
- Ch. 19 - Nucleophilic Acyl Substitution 2: Carboxylic Acid Derivatives39
- Ch. 20 - Enolates: Carbonyl Addition and Substitution13
- Ch. 21 - Conjugated Systems 1: Stability and Addition Reactions56
- Ch. 22 - Conjugated Systems 2: Pericyclic Reactions54
- Ch. 23 - Benzene 1: Aromatic Stability and Substitution Reactions64
- Ch. 24 - Benzene 2: Reactions Influenced by the Aromatic Ring62
- Ch. 25 - Amines: Structure, Reactions, and Synthesis27
- Ch. 26 - Amino Acids, Proteins, and Peptide Synthesis9
- Ch. 27 - Carbohydrates, Nucleic Acids, and Lipids54
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Non è quello che usi tu?Cambia libro di testo
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Mullins 1st EditionCh. 2 - General Chemistry Translated: Finding the ElectronsProblema 87
Mullins 1st EditionCh. 2 - General Chemistry Translated: Finding the ElectronsProblema 87Capitolo 1, Problema 87
In comparison to CH3- in Assessment 2.86, the related molecule BH4- is itself not a Lewis base at boron. Why?
Guida verificata passo dopo passo1
Understand the concept of a Lewis base: A Lewis base is a species that donates a pair of electrons to form a covalent bond. This requires the presence of a lone pair of electrons on the atom in question.
Analyze the structure of CH₃⁻: In CH₃⁻, the carbon atom has a lone pair of electrons, making it capable of donating this pair and acting as a Lewis base.
Examine the structure of BH₄⁻: In BH₄⁻, the boron atom is surrounded by four hydrogen atoms, forming a tetrahedral structure. Boron in this case has a full octet due to the bonding with the hydrogens.
Determine the availability of lone pairs on boron in BH₄⁻: Unlike CH₃⁻, boron in BH₄⁻ does not have a lone pair of electrons. All of its valence electrons are involved in bonding with the hydrogen atoms.
Conclude why BH₄⁻ is not a Lewis base: Since boron in BH₄⁻ lacks a lone pair of electrons to donate, it cannot act as a Lewis base, even though the molecule carries a negative charge. This is a key distinction from CH₃⁻.
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Lewis Acids and Bases
Lewis acids are electron pair acceptors, while Lewis bases are electron pair donors. In the context of boron and carbon compounds, understanding these definitions is crucial for determining the reactivity and classification of molecules. For instance, CH₃⁻ is a Lewis base because it can donate an electron pair, whereas BH₄⁻ does not behave as a Lewis base due to the electron deficiency of boron.
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02:49
The Lewis definition of acids and bases.
Electron Deficiency in Boron
Boron is an electron-deficient element, typically forming three covalent bonds and having an incomplete octet. This characteristic makes boron less likely to donate electron pairs, which is a key trait of Lewis bases. In BH₄⁻, the boron atom is surrounded by four hydrogens, stabilizing its electron configuration but not allowing it to act as a base.
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03:54The 18 and 16 Electron Rule
Resonance and Stability
Resonance refers to the delocalization of electrons across multiple structures, which can stabilize a molecule. In the case of BH₄⁻, the resonance structures do not allow for the boron atom to effectively donate an electron pair, as the overall stability of the molecule is maintained without it acting as a Lewis base. This contrasts with CH₃⁻, where the carbon can easily donate its lone pair.
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03:43The radical stability trend.
Pratica correlata
Domanda del libro di testo
Looking ahead in Chapter 3, we describe how the formal charge on an atom can be used to predict the number of lone pairs. Given the charge, or lack of charge, on each atom, fill in the electron pairs.
(a)
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Domanda del libro di testo
In Chapter 4, we explain that molecules like CH3- are Lewis bases or electron pair donors. What makes it a Lewis base?
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