为什么许多过渡金属配合物（如硫酸铜溶液、血红素）带有鲜艳的颜色？
Why are so many transition-metal complexes, such as copper sulfate solution or heme, brightly coloured?
过渡金属离子的 d 轨道在配体电场作用下发生能级分裂，分裂能的大小恰好落在可见光光子能量范围。电子在分裂后的 d 轨道之间跃迁（d-d 跃迁）时吸收特定波长的可见光，剩下的光被我们看到，配合物因此呈现补色。配体不同、分裂能不同，吸收波长就不同，所以六水合铜离子呈蓝色，而四氨合铜离子呈深蓝。有些颜色还来自配体到金属的电荷转移跃迁，如高锰酸钾的紫色，血红蛋白的颜色则来自铁-卟啉体系对可见光的选择性吸收。
In the electric field of ligands, the d orbitals of a transition-metal ion split into different energies, and the splitting gap falls right in the energy range of visible light. When an electron jumps between split d orbitals (a d-d transition), it absorbs light of a specific wavelength, and we see the complementary colour of what remains. Different ligands give different splittings, hence different absorbed wavelengths - so the hexaaqua copper ion is blue while the tetraammine copper ion is deep blue. Some colours come from ligand-to-metal charge transfer, as in the purple of permanganate, and the colour of hemoglobin arises from the selective visible absorption of the iron-porphyrin system.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 来源待核验 · Source pending review
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出处备注：著录仅给书名，无版次与年份；同一书名常对应多个版次，不臆测具体版本。
《普通化学》（配位化学）
General Chemistry (coordination chemistry)
#配合物 #d轨道 #颜色
稀有气体为什么也能液化？色散力是怎样产生的？
Why can noble gases liquefy, and how does the dispersion force arise?
惰性气体原子虽无永久偶极，但电子云的瞬时涨落会产生瞬时偶极，诱导邻近原子产生诱导偶极，两者相互吸引，这就是色散力（伦敦力）。色散力随电子数增多、极化率增大而增强，所以从氦到氙沸点逐步升高。它存在于一切分子之间，是非极性分子间唯一的吸引来源。
Although noble-gas atoms have no permanent dipole, instantaneous fluctuations of their electron clouds create transient dipoles that induce dipoles in neighbors, which attract each other - this is the dispersion (London) force. It strengthens with electron count and polarizability, so boiling points rise steadily from helium to xenon. It operates between all molecules and is the only attraction among nonpolar ones.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
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Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#色散力 #极化率 #分子间作用力
乙烯分子中的pi键是怎样形成的？
How is the pi bond in ethene formed?
乙烯的两个碳各用三个sp2杂化轨道，在平面内以约120度角形成C-C sigma键和C-H sigma键；每个碳剩下的一个未杂化p轨道垂直于分子平面，两个p轨道侧面重叠形成pi键。pi电子云分布在平面上下，结合较弱，容易被试剂进攻，所以烯烃容易发生亲电加成反应。
Each carbon of ethene uses three sp2 hybrids to form the C-C sigma bond and C-H sigma bonds, arranged at about 120 degrees in a plane; each carbon's remaining unhybridized p orbital stands perpendicular to the plane, and the two p orbitals overlap side-on to form the pi bond. The pi electrons sit above and below the plane, are weakly held, and are easily attacked, which is why alkenes undergo electrophilic addition.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
邢其毅 等,《基础有机化学》第4版,北京大学出版社,2016
Xing Qiyi et al., Basic Organic Chemistry, 4th ed., Peking University Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787301272121（豆瓣书目条目: 基础有机化学）
#sp2杂化 #pi键 #烯烃
氟化氢的沸点为什么反常地高于氯化氢？
Why is the boiling point of HF anomalously higher than that of HCl?
HF分子间能形成相当强的F-H...F氢键，液态HF中还存在链状的氢键网络，打断这些氢键需要大量能量，所以其沸点约19.5摄氏度，反常地高。HCl分子间只有色散力，分子量虽更大，沸点却仅约零下85摄氏度。氢键使HF成为卤化氢中沸点最高者。
HF molecules form quite strong F-H...F hydrogen bonds, and liquid HF has chain-like hydrogen-bonded networks; breaking them requires substantial energy, so HF boils at about 19.5 degrees Celsius, anomalously high. HCl molecules interact only through dispersion forces, so despite a larger molar mass it boils at about -85 degrees Celsius. Hydrogen bonding makes HF the highest-boiling hydrogen halide.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#氢键 #氟化氢 #反常沸点
一氧化碳（CO）和氮气（N₂）电子数相同，为什么 CO 有偶极矩而 N₂ 没有？
Carbon monoxide (CO) and nitrogen (N₂) are isoelectronic, so why does CO have a dipole moment while N₂ does not?
N₂ 完全对称、两端电负性相同，偶极矩为零。CO 中氧虽电负性更大，但氧的一个孤对电子以配位键形式提供给碳，且分子的主要共振结构为 ⁻C≡O⁺（碳端带部分负电荷、氧端带部分正电荷），这一电子分布压倒了电负性效应，使净偶极约 0.11 D、方向指向碳端。
N₂ is symmetric with identical end atoms, so its dipole is zero. In CO the more electronegative oxygen would pull electron density toward itself, but one of oxygen's lone pairs is donated to carbon as a dative bond and the dominant resonance form is −C≡O+ (partial negative on carbon, partial positive on oxygen). This distribution outweighs the electronegativity effect, giving CO a net dipole of about 0.11 D pointing toward the carbon end.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-03
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Atkins & de Paula《物理化学》（第10版），第16章分子结构
Atkins & de Paula, "Physical Chemistry" (10th ed.), Ch.16
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL1907523W：Physical chemistry（首版 1
#偶极矩 #等电子体 #π反馈键 #一氧化碳
什么是电负性？它如何影响化学键的极性？
What is electronegativity and how does it affect bond polarity?
电负性是原子在分子中吸引成键电子能力的量度，鲍林标度中最强的是氟（约4.0）。当两个原子电负性差很大时形成离子键，差较小时形成极性共价键，相等时形成非极性共价键。电负性差越大，键的极性越强。
Electronegativity measures an atom's ability to attract bonding electrons; on the Pauling scale fluorine is the strongest at about 4.0. A large electronegativity difference yields ionic character, a small one gives polar covalent bonds, and zero gives nonpolar bonds. The greater the difference, the more polar the bond.
难度 进阶 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#电负性 #鲍林标度 #键极性
氨分子为什么是三角锥形而不是平面三角形？
Why is the ammonia molecule trigonal-pyramidal rather than planar trigonal?
氮有5个价电子，与三个氢成键后还剩一对孤对电子。四对电子对按四面体方向排斥，孤对电子占据一个位置，把三个N-H键压缩到约107度，因此氨呈三角锥形。孤对电子还能结合质子，这正是氨气呈碱性的原因。
Nitrogen has five valence electrons and, after bonding to three hydrogens, still has one lone pair. The four electron pairs repel toward tetrahedral directions; the lone pair occupies one position and compresses the N-H bonds to about 107 degrees, giving ammonia a trigonal-pyramidal shape. The lone pair can also accept a proton, which is why ammonia is basic.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
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《普通化学》(Atkins) 分子结构章节
General Chemistry (Atkins), molecular structure
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL8206954W：General Chemistry Ise A
#VSEPR #氨 #孤对电子
为什么冰比水轻？
Why is ice less dense than water?
水结冰时，分子间氢键形成规则的六方晶格，使分子间距增大、结构疏松。因此冰的密度比液态水小，能浮在水面上。这一性质对水生生物的越冬保护非常重要。
When water freezes, intermolecular hydrogen bonds form a regular hexagonal lattice that spreads the molecules apart and makes the structure loose. Ice is therefore less dense than liquid water and floats on it. This property is crucial for protecting aquatic life in winter.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
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Brown、LeMay、Bursten 等《化学：中心科学》（第14版，Pearson）水的性质与氢键章节
Brown, T. L.; LeMay, H. E.; Bursten, B. E.; et al. Chemistry: The Central Science, 14th ed., Pearson (properties of water; hydrogen bonding)
独立核验依据 · Independent verification: 核验依据 1 ARCHIVE 标识 studentlectureno00theo：Chemistry, the central
#冰 #密度 #氢键
血红蛋白为什么能抓住氧气，又能在组织里把它放出来？
Why can hemoglobin capture oxygen and then release it in the tissues?
血红蛋白分子中心的血红素是一个卟啉环配合物，铁离子位于环中央，通过配位键与四个氮原子结合，还保留着一个空位。肺部氧分压高时，氧分子以配位键挂到铁离子上，形成氧合血红蛋白；到组织处氧分压降低，配位键变弱，氧就被释放。这本质上是金属配合物的可逆配位平衡：氧充足时结合，氧浓度下降时解离，铁离子就是氧的装卸站。
In the center of hemoglobin sits heme, a porphyrin-ring complex with an iron ion held at the middle by coordinate bonds to four nitrogen atoms, leaving one site free. In the lungs, where oxygen partial pressure is high, an O2 molecule coordinates to the iron, forming oxyhemoglobin; in the tissues the pressure is low, the coordinate bond weakens, and oxygen is released. This is essentially a reversible coordination equilibrium of a metal complex: binding when oxygen is plentiful, dissociation when it is scarce - the iron ion is the loading dock for oxygen.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#血红蛋白 #配位键 #铁
为什么石墨能导电而金刚石不能？
Why can graphite conduct electricity but diamond cannot?
石墨中碳原子呈层状排列，每层内有离域的π电子可在层内自由移动，因此能导电。金刚石中每个碳都以sp3杂化形成四个定域共价键，没有自由电子，故不导电。两者都是碳的同素异形体，性质却截然不同。
In graphite, carbon atoms form layers with delocalized pi electrons that can move freely within a layer, so it conducts. In diamond, each carbon is sp3 hybridized into four localized covalent bonds with no free electrons, so it does not conduct. Both are allotropes of carbon yet behave very differently.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
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Brown、LeMay、Bursten 等《化学：中心科学》（第14版，Pearson）碳的同素异形体（石墨与金刚石）章节
Brown, T. L.; LeMay, H. E.; Bursten, B. E.; et al. Chemistry: The Central Science, 14th ed., Pearson (allotropes of carbon: graphite and diamond)
独立核验依据 · Independent verification: 核验依据 1 ARCHIVE 标识 studentlectureno00theo：Chemistry, the central
#石墨 #金刚石 #导电
σ 键和 π 键在形成方式和性质上有什么不同？
How do sigma (σ) and pi (π) bonds differ in how they form and in their properties?
σ 键由原子轨道沿键轴"头碰头"重叠形成，电子云绕轴呈圆柱形对称，可绕轴自由旋转、键较强。π 键由 p 轨道"肩并肩"侧向重叠形成，电子云分布在键轴上下，不能绕轴自由旋转、键较弱且较易断裂。
A sigma bond forms by head-on overlap of orbitals along the bond axis, giving cylindrically symmetric electron density that allows free rotation and is relatively strong. A pi bond forms by side-on overlap of p orbitals above and below the axis, blocks free rotation, and is weaker and more easily broken.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
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McMurry《有机化学》（第9版），第1章共价键
McMurry, "Organic Chemistry" (9th ed.), Ch.1
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL57249W：Organic chemistry（首版 1984
#σ键 #π键 #轨道重叠 #共价键
什么是极性键和非极性键？
What are polar and nonpolar covalent bonds?
当两个相同原子成键时，电子对均分，形成非极性键，如氧气中的氧氧键。当两个电负性不同的原子成键时，电子对偏向电负性大的一方，形成极性键，如水中的氧氢键。键的极性影响分子极性和溶解性。
When two identical atoms bond, the electron pair is shared equally, forming a nonpolar bond, such as the O-O bond in oxygen. When atoms of different electronegativity bond, the pair shifts toward the more electronegative atom, forming a polar bond, such as the O-H bond in water. Bond polarity affects molecular polarity and solubility.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
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Brown、LeMay、Bursten 等《化学：中心科学》（第14版，Pearson）极性共价键章节
Brown, T. L.; LeMay, H. E.; Bursten, B. E.; et al. Chemistry: The Central Science, 14th ed., Pearson (polar covalent bonds)
独立核验依据 · Independent verification: 核验依据 1 ARCHIVE 标识 studentlectureno00theo：Chemistry, the central
#极性键 #非极性键 #电负性
为什么水的沸点远高于分子量相近的硫化氢和氨？
Why is water's boiling point far higher than that of H2S or NH3 despite similar molar masses?
氢键的强度通常高于范德华力。水分子间形成O-H...O氢键，需要更多热能才能挣脱，所以沸点高达100摄氏度；硫化氢几乎无氢键，氨的氢键又弱于水，因此沸点都低得多。氢键还使水的比热容、熔化热异常偏大，形成许多反常性质。
Hydrogen bonds are typically stronger than van der Waals forces. Water molecules form O-H...O hydrogen bonds that take more thermal energy to break, so water boils at 100 degrees Celsius; H2S has almost no hydrogen bonding and NH3 forms weaker bonds, so both boil much lower. Hydrogen bonding also gives water its unusually large heat capacity and enthalpy of fusion.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#氢键 #沸点 #反常性质
什么是杂化轨道？以甲烷为例说明。
What is orbital hybridization? Explain using methane.
杂化是原子在成键时把能量相近的原子轨道混合，重新组合成数目相等、方向更合理的新轨道。甲烷中碳的一个 2s 与三个 2p 轨道杂化为四个等价的 sp³ 轨道，指向正四面体四个顶点，键角约109.5°。
Hybridization mixes atomic orbitals of similar energy to form new equivalent orbitals oriented for bonding. In methane, carbon's one 2s and three 2p orbitals hybridize into four equivalent sp³ orbitals pointing to a tetrahedron's corners, with bond angles near 109.5°.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-02
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周公度《结构化学基础》
Structural Chemistry (Zhou Gongdu)
独立核验依据 · Independent verification: 核验依据 1 ISBN 9787301283073（豆瓣书目条目: 结构化学基础）
#杂化 #sp³ #甲烷
甲烷为什么是正四面体形？碳原子怎样形成四个完全等价的C-H键？
Why is methane tetrahedral, and how does carbon form four identical C-H bonds?
碳原子把2s轨道和三个2p轨道杂化成四个能量相同的sp3杂化轨道，每个轨道与一个氢的1s轨道沿轴向重叠成键。四个sp3杂化轨道指向正四面体的四个顶点，夹角约109.5°，所以甲烷是正四面体形，四个C-H键完全等价。
Carbon hybridizes its 2s and three 2p orbitals into four equivalent sp3 hybrid orbitals, each overlapping a hydrogen 1s orbital along its axis to form a bond. The four sp3 hybrids point to the corners of a regular tetrahedron with angles of about 109.5°, so methane is tetrahedral with four fully equivalent C-H bonds.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
邢其毅 等,《基础有机化学》第4版,北京大学出版社,2016
Xing Qiyi et al., Basic Organic Chemistry, 4th ed., Peking University Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787301272121（豆瓣书目条目: 基础有机化学）
#杂化轨道 #sp3 #甲烷
水分子为什么是弯曲的（V形）而不是直线形的？
Why is the water molecule bent rather than linear?
根据VSEPR（价层电子对互斥）理论，氧原子有6个价电子，与两个氢成键后还剩两对孤对电子。四对电子对按四面体方向互相排斥，两对孤对电子排斥力更强，把O-H键压缩到约104.5°，所以水分子呈弯曲状而不是直线形。孤对电子不参与成键，却决定了分子的整体形状。
By VSEPR (valence-shell electron-pair repulsion) theory, oxygen has six valence electrons and, after bonding to two hydrogens, keeps two lone pairs. The four electron pairs repel toward tetrahedral directions, and the two lone pairs repel more strongly, squeezing the O-H bonds to about 104.5°, so the molecule is bent rather than linear. Lone pairs do not bond but still fix the overall shape.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
《普通化学》(Atkins) 分子结构章节
General Chemistry (Atkins), molecular structure
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL8206954W：General Chemistry Ise A
#VSEPR #分子形状 #孤对电子
为什么水分子是弯曲形的而不是直线形？
Why is the water molecule bent rather than linear?
氧原子在 H₂O 中有两对成键电子和两对孤对电子，根据价层电子对互斥理论（VSEPR），电子对彼此排斥使空间排布趋向四面体。孤对电子占据更多空间，把两个 O–H 键压向约104.5°，因此分子呈弯曲形。
In H₂O the oxygen has two bonding pairs and two lone pairs; VSEPR theory predicts electron pairs repel to a roughly tetrahedral arrangement. Lone pairs occupy more space and push the O–H bonds to about 104.5°, giving a bent shape.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03
来源 · Source
《无机化学》（北京师范大学等编）
Inorganic Chemistry (Beijing Normal Univ.)
#价层电子对互斥 #孤对电子 #分子构型
什么是极性分子和非极性分子？
What are polar and nonpolar molecules?
极性分子中电荷分布不均匀，一端偏正一端偏负，如水。非极性分子电荷分布均匀，如氧气和二氧化碳。分子的极性取决于键的极性和分子形状。
In a polar molecule, charge is unevenly distributed with a positive and a negative end, as in water. A nonpolar molecule has even charge distribution, like oxygen or carbon dioxide. Polarity depends on both bond polarity and molecular shape.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#极性分子 #非极性 #电荷
什么是金属键？
What is a metallic bond?
金属键是金属原子释放出的自由电子与金属阳离子之间形成的相互作用。这些自由电子像海洋一样流动，使得金属能够导电和导热。
A metallic bond is the interaction between the free electrons released by metal atoms and the metal cations. These free electrons flow like a sea, allowing metals to conduct electricity and heat.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#金属键 #自由电子 #导电
什么是范德华力？它和氢键是什么关系？
What are van der Waals forces, and how do they relate to hydrogen bonds?
范德华力是分子间弱相互作用的总称，包括取向力、诱导力和色散力，强度通常为每摩尔几到几十千焦，比共价键弱得多。氢键是一种特殊的、方向性强的偶极-偶极作用，强度在范德华力和共价键之间，传统上把它单独列为一类分子间作用力。
Van der Waals forces are the weak interactions between molecules, including orientation, induction and London dispersion forces, typically a few to tens of kilojoules per mole, far weaker than covalent bonds. A hydrogen bond is a directional dipole-dipole interaction intermediate in strength between van der Waals forces and covalent bonds, and is usually classified on its own.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#范德华力 #色散力 #氢键
水黾为什么能站在水面上？这源于水的什么性质？
Why can water striders stand on water, and which property of water is involved?
这源于水的表面张力。表面层的水分子受到下方水分子的净吸引，使液面趋向收缩，形成类似弹性薄膜的界面。水的氢键网络使它的表面张力在常见液体中很高，足以托住水黾这类轻小昆虫；露珠在荷叶上滚成球形，也是表面张力的表现。
It comes from surface tension. Molecules at the surface are pulled inward, making the surface shrink like an elastic skin. Because hydrogen bonding gives water one of the highest surface tensions among common liquids, this skin can support light insects such as water striders; dew forming spherical droplets on lotus leaves is the same effect.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#表面张力 #氢键 #水
为什么氨气易溶于水？
Why is ammonia highly soluble in water?
氨分子是极性分子，且氮上有孤对电子，能与水分子形成氢键。同时氨在水中部分反应生成铵离子和氢氧根，进一步促进溶解。因此氨气在水中溶解度很大，1体积水可溶解约700体积氨。
Ammonia is a polar molecule and its nitrogen has a lone pair that can form hydrogen bonds with water. It also partly reacts in water to form ammonium and hydroxide ions, further aiding dissolution. As a result ammonia is very soluble: about 700 volumes of gas dissolve in one volume of water.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
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Brown、LeMay、Bursten 等《化学：中心科学》（第14版，Pearson）氨的性质与氢键章节
Brown, T. L.; LeMay, H. E.; Bursten, B. E.; et al. Chemistry: The Central Science, 14th ed., Pearson (properties of ammonia; hydrogen bonding)
独立核验依据 · Independent verification: 核验依据 1 ARCHIVE 标识 studentlectureno00theo：Chemistry, the central
#氨 #溶解度 #氢键
为什么CO2是直线形而SO2是V形？
Why is CO2 linear but SO2 bent?
CO2中碳为sp杂化，无孤对电子，两个双键对称分布，分子呈直线形。SO2中硫有一对孤对电子，sp2杂化下孤对电子压缩键角，使分子呈V形。孤对电子的存在是二者形状不同的关键。
In CO2, carbon is sp hybridized with no lone pairs, so the two double bonds are symmetric and the molecule is linear. In SO2, sulfur has one lone pair; under sp2 hybridization the lone pair compresses the bond angle, giving a bent shape. The presence of a lone pair is the key difference.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
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Brown、LeMay、Bursten 等《化学：中心科学》（第14版，Pearson）价层电子对互斥理论与分子形状章节
Brown, T. L.; LeMay, H. E.; Bursten, B. E.; et al. Chemistry: The Central Science, 14th ed., Pearson (VSEPR; shapes of CO2 and SO2)
独立核验依据 · Independent verification: 核验依据 1 ARCHIVE 标识 studentlectureno00theo：Chemistry, the central
#分子形状 #杂化 #孤对电子
什么是分子间作用力？
What are intermolecular forces?
分子间作用力是分子与分子之间的微弱吸引力，包括范德华力和氢键。它们决定了物质的熔沸点、溶解性等物理性质。相比化学键，分子间作用力弱得多，但累积起来对物质状态影响巨大。
Intermolecular forces are weak attractions between molecules, including van der Waals forces and hydrogen bonds. They determine physical properties such as melting and boiling points and solubility. Though much weaker than chemical bonds, their cumulative effect strongly influences the state of matter.
难度 入门 · 适合 大众
CC BY 4.0 · 来源待核验 · Source pending review
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出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
Atkins 与 de Paula《物理化学》（第10版，牛津大学出版社）分子间作用力章节
Atkins, P. W.; de Paula, J. Physical Chemistry, 10th ed., Oxford University Press (intermolecular forces)
#分子间作用力 #范德华力 #物理性质
共价键与离子键有什么本质区别？
What is the essential difference between covalent and ionic bonds?
共价键是相邻原子通过共用电子对形成的化学键，常见于非金属原子之间，如 H₂、O₂、CH₄。离子键靠电子完全转移形成阴阳离子后靠静电结合。共价分子通常熔点较低，熔化后一般不导电。
A covalent bond forms when neighboring atoms share electron pairs, common among nonmetals such as in H₂, O₂, and CH₄. Ionic bonds arise from complete electron transfer creating oppositely charged ions held together electrostatically. Covalent substances generally have lower melting points and do not conduct electricity when melted.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#共价键 #共用电子对 #非金属
双键和三键有什么区别？
What is the difference between a double bond and a triple bond?
双键由两对共用电子构成，三键由三对共用电子构成。键级越高，键长越短、键能越大，分子越稳定但旋转受限。例如乙烯含碳碳双键，乙炔含碳碳三键。
A double bond consists of two shared electron pairs and a triple bond of three pairs. Higher bond order gives a shorter, stronger bond and greater stability but restricts rotation. For example, ethylene has a carbon-carbon double bond and acetylene a triple bond.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
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Brown、LeMay、Bursten 等《化学：中心科学》（第14版，Pearson）共价键与键级章节
Brown, T. L.; LeMay, H. E.; Bursten, B. E.; et al. Chemistry: The Central Science, 14th ed., Pearson (covalent bond order)
独立核验依据 · Independent verification: 核验依据 1 ARCHIVE 标识 studentlectureno00theo：Chemistry, the central
#双键 #三键 #键级
氢键是什么？为什么它很重要？
What is a hydrogen bond and why is it important?
氢键是氢原子与电负性很强的原子（如 N、O、F）共价结合后，再与另一电负性原子之间产生的弱静电吸引。它比普通共价键弱得多，但远强于范德华力，决定了水的异常高沸点、DNA 双螺旋的稳定以及蛋白质折叠。
A hydrogen bond is a weak electrostatic attraction when hydrogen, bonded to a highly electronegative atom such as N, O, or F, interacts with another electronegative atom. Much weaker than covalent bonds but stronger than van der Waals forces, it underlies water's high boiling point, DNA double-helix stability, and protein folding.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#氢键 #水 #DNA
离子键和共价键有什么区别？
What is the difference between ionic and covalent bonds?
离子键由原子间电子的完全转移形成阴阳离子、靠静电引力结合，常见于活泼金属与非金属之间。共价键由原子间共用电子对形成，常见于非金属之间。两者的成键方式和物理性质（如熔沸点、导电性）差异明显。
An ionic bond forms when electrons are completely transferred between atoms to make cations and anions held by electrostatic attraction, common between active metals and nonmetals. A covalent bond forms by sharing electron pairs, common among nonmetals. Their bonding mode and physical properties such as melting point and conductivity differ markedly.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
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Brown、LeMay、Bursten 等《化学：中心科学》（第14版，Pearson）化学键（离子键与共价键）章节
Brown, T. L.; LeMay, H. E.; Bursten, B. E.; et al. Chemistry: The Central Science, 14th ed., Pearson (ionic and covalent bonding)
独立核验依据 · Independent verification: 核验依据 1 ARCHIVE 标识 studentlectureno00theo：Chemistry, the central
#离子键 #共价键 #成键
金属为什么能导电和传热？
Why can metals conduct electricity and heat?
金属原子释放出可在整块金属中自由移动的电子，形成电子海。这些自由电子既能携带电荷，也能携带能量，所以金属善于导电导热。
Metal atoms release electrons that move freely throughout the metal, forming an electron sea. These free electrons carry both charge and energy, so metals conduct electricity and heat well.
难度 入门 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#金属 #自由电子 #导电
什么是离子键？
What is an ionic bond?
离子键是带正电的阳离子与带负电的阴离子之间通过静电吸引力形成的化学键。它常见于活泼金属与活泼非金属之间，如钠与氯反应生成氯化钠（Na⁺Cl⁻）。离子化合物通常熔点高，熔融态或水溶液中能导电。
An ionic bond is the electrostatic attraction between positively charged cations and negatively charged anions. It commonly forms between reactive metals and nonmetals, as in sodium and chlorine yielding sodium chloride. Ionic compounds typically have high melting points and conduct electricity when molten or in solution.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#离子键 #静电引力 #氯化钠
σ 键和 π 键有什么不同？
What is the difference between sigma and pi bonds?
σ 键是原子沿核间轴头碰头重叠，可自由旋转、强度高；π 键是 p 轨道肩并肩重叠，存在于双键/三键中，不能旋转且较弱，电子暴露于键轴上下。
A sigma bond is end-to-end overlap along the internuclear axis, allowing free rotation and strong bonding; a pi bond is side-by-side p-orbital overlap in double/triple bonds, cannot rotate, is weaker, and places electrons above and below the axis.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#共价键 #轨道重叠 #双键
什么是氢键？
What is a hydrogen bond?
氢键是氢原子与电负性很强的原子（如氧、氮、氟）共价结合后，再与另一电负性原子之间产生的较强分子间作用力。它比范德华力强，但远弱于化学键。氢键使水具有高沸点，也是DNA双螺旋稳定的重要原因。
A hydrogen bond forms when a hydrogen atom covalently bound to a highly electronegative atom such as oxygen, nitrogen or fluorine is attracted to another electronegative atom. It is stronger than van der Waals forces but much weaker than a chemical bond. Hydrogen bonding gives water its high boiling point and helps stabilize the DNA double helix.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#氢键 #分子间作用力 #水
金属键的“电子海”模型是什么？
What is the 'electron sea' model of metallic bonding?
金属原子把价电子贡献到整个晶体共享的离域电子海中，正离子实浸泡其中，靠静电吸引结合。这解释了金属导电、导热、延展与金属光泽。
Metal atoms contribute valence electrons into a delocalized 'sea' shared across the crystal, with positive ions bathed in it, held by electrostatic attraction. This explains electrical/thermal conductivity, malleability, and metallic luster.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
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大连理工大学无机化学教研室 编,《无机化学》第6版,高等教育出版社
Dalian University of Technology Inorganic Chemistry Group, Inorganic Chemistry, 6th ed., Higher Education Press
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787040492750（豆瓣书目条目: 无机化学）
#金属键 #电子海 #导电
食盐是离子化合物吗？
Is table salt an ionic compound?
是的。食盐的化学成分是氯化钠，由带正电的钠离子和带负电的氯离子通过静电吸引结合而成，属于典型的离子化合物。
Yes. Table salt is sodium chloride, formed by positively charged sodium ions and negatively charged chloride ions held together by electrostatic attraction, making it a typical ionic compound.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#食盐 #离子化合物 #氯化钠
为什么把食盐放进水里搅一搅，盐就"化掉"看不见了？
Why does table salt seem to "disappear" when stirred into water?
食盐是钠离子和氯离子靠静电吸引组成的晶体。水分子一头带正电、一头带负电，会包围并拉住这些离子，把它们一个个从晶体上"拽"进水里分散开，这叫水合作用，于是肉眼就看不见盐了。
Table salt is a crystal of sodium and chloride ions held by electrostatic attraction. Water molecules have a positive end and a negative end, so they surround and pull the ions off the crystal one by one, spreading them through the water—a process called hydration—so the solid becomes invisible.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-11-03
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Brown, LeMay & Bursten《化学：中心科学》（第14版），第4章
Brown, LeMay & Bursten, "Chemistry: The Central Science" (14th ed.), Ch.4
独立核验依据 · Independent verification: 核验依据 1 ARCHIVE 标识 studentlectureno00theo：Chemistry, the central
#溶解 #水合 #离子 #食盐
什么是化学键？
What is a chemical bond?
化学键是原子之间强烈的相互作用，它把原子结合成分子或晶体。常见的化学键有离子键、共价键和金属键三种。
A chemical bond is a strong attraction between atoms that holds them together in molecules or crystals. The three common types are ionic bonds, covalent bonds, and metallic bonds.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#化学键 #离子键 #共价键