Name: how bond polarity shapes molecular dipoles
Uploaded: 2020-09-03T13:38:28.000Z
Duration: 2 min 48 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

NC K-12 Science Standard Course of Study

9-12

Chemistry

Matter and its Interactions

PS.Chm.3.1

bond-polarity-dipole-moment-and-percent-ionic-character

Bond Polarity, Dipole Moment, and Percent Ionic Character

화학 결합의 종류는 그것이 비극성 공유, 극성 공유 또는 이온성이든 간에, 주로 결합 원자의 전기 음성도의 차이와 결합 길이로 결정됩니다. 브롬에서 두 브롬 원자의 결합은 그것들 사이의 전기 음성도 차이가 0이기 때문에 극성이 아닙니다. 브롬화수소의 경우, 전기음성도가 센 브롬이 전기적 음성이 약한 수소 원자로부터 전자 밀도를 끌어 당기기 때문에 결합은 극성 공유입니다.

브롬화칼륨에서는 전기 음성도 차이가 훨씬 커서 이온성 결합으로 되며 칼륨에서 브롬 쪽으로 전자가 완전히 이동합니다. 두 개의 입자는 동등하지만 반대 전하를 띤 입자들은 쌍극자가 형성되는 거리만큼 분리됩니다. 쌍극자의 정량적인 측정을 쌍극자 모멘트라 하는데, 문자 뮤 로 표현합니다.

이는 쿨롱 단위의 전하 크기 Q와 미터 단위의 전하 사이 거리 r를 곱한 값입니다. 쌍극자 모멘트는 디바이 단위로 주어지며, 여기서 일 디바이는 3.34 곱하기 10의 마이너스 30승 쿨롱 미터입니다. 화합물이 극성 공유인지 이온성인지 여부는 이온 특성 백분율을 계산하여 결정할 수 있는데, 이것은 결합의 측정된 쌍극자 모멘트와 완전한 전자의 이동을 가정했을 때의 쌍극자 모멘트의 비입니다.

이온성이 50%이상인 결합은 이온성으로 간주됩니다. 이제 불화수소를 고려해 봅시다. 수소와 불소 원자가 92 피코미터 만큼 떨어져 있습니다.

결합이 이온성인 경우, 쌍극자 모멘트는 완전한 전자 이동을 가정하여 계산됩니다. 전자의 전하를 원자 사이의 거리로 곱하고, 얻어진 값을 일 디바이로 나누면 쌍극자 모멘트는 4.41 D로 얻어집니다. 그러나 실험적으로 측정한 불화 수소의 쌍극자 모멘트는 1.18 D입니다.

따라서 불화수소의 이온 특성 백분율을 결정하기 위해 1.18 D의 측정값을 4.41D로 나누면 41%의 이온 특성 백분율이 얻어집니다. 불화수소의 이온 특성 백분율이 50%미만이기 때문에 극성 공유 결합입니다.

결합 극성, 쌍극자 모멘트 및 백분율 이온 특성

결합의 극성

결합된 두 원자의 전기음성도 차이(ΔEN)의 절대값은 결합에서 예상되는 극성, 즉 결합 유형에 대한 대략적인 척도를 제공합니다. 차이가 매우 작거나 0이면 결합은 공유 결합이고 비극성입니다. 크기가 클 경우 결합은 극성 공유 결합 또는 이온 결합입니다. H–H, H–Cl 및 Na–Cl 결합의 원자 사이의 전기 음성도 차이의 절대값은 각각 0(비극성), 0.9(극성 공유 결합) 및 2.1(이온성)입니다.

원자 간에 전자가 공유되는 정도는 완전히 동일한 것(순수 공유 결합)부터 전혀 공유되지 않는 것(이온 결합)까지 다양합니다.

<ol style="list-style-type: disc;">
	<li>예를 들어, HF의 H와 F 원자의 전기음성도 차이는 1.9이고, NH_3의 N과 H 원자의 전기음성도 차이는 0.9이지만, 이 두 화합물은 모두 극성 공유로 간주되는 결합을 형성합니다.</li>
	<li>마찬가지로 NaCl의 Na와 Cl 원자의 전기음성도 차이는 2.1이고, MnI_2의 Mn과 I 원자의 전기음성도 차이는 1.0이지만, 이 두 물질은 모두 이온 화합물을 형성합니다.</li>
</ol>

결합의 공유 결합 또는 이온 특성에 대한 가장 좋은 지침은 관련된 원자의 유형과 주기율표에서의 상대적 위치를 고려하는 것입니다.

<ol style="list-style-type: disc;">
	<li>두 비금속 사이의 결합은 일반적으로 공유 결합입니다.</li>
	<li>금속과 비금속 사이의 결합은 종종 이온성입니다.</li>
</ol>

일부 화합물에는 공유 결합과 이온 결합이 모두 포함되어 있습니다. OH^-, NO_3^-, NH_4^+와 같은 다원자 이온의 원자는 극성 공유 결합으로 서로 결합되어 있습니다. 그러나 이러한 다원자 이온은 반대 전하의 이온과 결합하여 이온 화합물을 형성합니다. 예를 들어, 질산칼륨 KNO_3에는 K^+ 양이온과 다원자 NO_3^− 음이온이 포함되어 있습니다. 따라서 질산칼륨의 결합은 이온성이며, 이는 K^+ 이온과 NO_3^- 이온 사이의 정전기적 인력뿐만 아니라 NO_3^-의 질소와 산소 원자 사이의 공유 결합으로 인해 발생합니다.

분자 극성 및 쌍극자 모멘트

이전에 논의한 바와 같이, 극성 공유 결합은 전기음성도가 다른 두 원자를 연결하여 전자가 전기음성도가 더 높은 원자 쪽으로 끌려가면서 한 원자는 부분 양전하(δ+)를, 다른 원자는 부분 음전하(δ-)를 갖게 됩니다. 이러한 전하 분리는 결합 쌍극자 모멘트를 발생시킵니다. 결합 쌍극자 모멘트의 크기는 그리스 문자 mu(μ)로 표시되며 여기에 표시된 공식으로 제공됩니다. 여기서 Q는 부분 전하의 크기(전기 음성도 차이로 결정됨)이고 r은 전하 사이의 거리입니다:

<img alt="Eq1" src="https://www.jove.com/files/core/CDNSource/lessons/1062/1062_Equations-01.png" style="height: 40px;" />

이 결합 모멘트는 방향과 크기를 모두 갖는 양인 벡터로 표현될 수 있습니다. 쌍극자 벡터는 전기음성도가 낮은 원자에서 전기음성도가 높은 원자 쪽으로 결합을 따라 가리키는 화살표로 표시됩니다. 결합의 부분적으로 양의 끝을 나타내기 위해 전기 음성도가 낮은 끝에 작은 더하기 기호가 그려집니다. 화살표의 길이는 두 원자 사이의 전기 음성도 차이의 크기에 비례합니다.

전체 분자는 분자 구조와 각 결합의 극성에 따라 전하 분리를 가질 수도 있습니다. 그러한 전하 분리가 존재하는 경우, 분자는 극성 분자(또는 쌍극자)라고 합니다. 그렇지 않으면 분자는 비극성이라고 합니다. 쌍극자 모멘트는 분자 전체의 순 전하 분리 정도를 측정합니다. 쌍극자 모멘트는 분자 구조를 고려하여 3차원 공간에서 결합 모멘트를 추가하여 결정됩니다.

이원자 분자의 경우 결합이 하나만 있으므로 결합 쌍극자 모멘트가 분자 극성을 결정합니다. Br_2와 N_2와 같은 동핵 이원자 분자는 전기 음성도에 차이가 없으므로 쌍극자 모멘트는 0입니다. CO와 같은 이핵 분자의 경우 작은 쌍극자 모멘트가 있습니다. HF의 경우 전기 음성도의 차이가 크기 때문에 쌍극자 모멘트가 더 큽니다.

분자가 둘 이상의 결합을 포함하는 경우 기하학적 구조를 고려해야 합니다. 분자의 결합이 결합 모멘트가 상쇄되도록 배열되면(벡터 합은 0과 같음) 분자는 비극성입니다. 이것이 CO_2의 상황입니다. 각 결합은 극성이지만 분자 전체는 비극성입니다. 루이스 구조와 VSEPR 이론을 사용하여 CO_2 분자는 탄소 원자의 반대편에 극성 C=O 결합이 있는 선형인 것으로 결정됩니다. 결합 모멘트는 반대 방향을 가리키기 때문에 상쇄됩니다. 물 분자의 경우, 루이스 구조는 중심 원자에 두 개의 결합이 있음을 다시 보여주고, 전기 음성도 차이는 이 결합 각각이 0이 아닌 결합 모멘트를 가짐을 다시 보여줍니다. 그러나 이 경우 O의 고립 쌍으로 인해 분자 구조가 구부러지고 두 결합 모멘트가 상쇄되지 않습니다. 따라서 물은 순 쌍극자 모멘트를 가지며 극성 분자(쌍극자)입니다.



이 문서는 에서 발췌되었습니다 <a href="https://openstax.org/books/chemistry-2e/pages/7-2-covalent-bonding">Openstax, Chemistry 2e, Chapter 7.2: Covalent Bonding and  Openstax, Chemistry 2e, Chapter 7.6 Molecular Structure and Polarity.</a>

본드 극성

두 결합 된 원자의 전기 음성도 (ΔEN)의 차이의 절대 값은 극성의 대략적인 측정을 제공합니다 ...

Education

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JoVE Core

화학

하나

Chemical Bonding: Basic Concepts

화학 결합: 기본 개념

KEY TERMS AND CONCEPTS

주요 용어 및 개념

how bond polarity shapes molecular dipoles

Bond polarity depends on electronegativity, the ability of an atom to attract shared electrons. The absolute value of the electronegativity difference, or ΔEN, gives a rough guide to bond type. When the difference is very small or zero, the bond is covalent and nonpolar. When it is larger, the bond may be polar covalent or ionic.

Examples show how this works in real compounds. H–H has a ΔEN of 0, so it is nonpolar. H–Cl has a ΔEN of 0.9, so it is polar covalent. Na–Cl has a ΔEN of 2.1, so it is ionic. Even so, ΔEN is only a guide. HF has a ΔEN of 1.9 and NH3 has a ΔEN of 0.9, yet both have polar covalent bonds. NaCl has a ΔEN of 2.1 and MnI2 has a ΔEN of 1.0, yet both are ionic compounds.

The type of atoms in the periodic table is often the best clue. Bonds between two nonmetals are generally covalent. Bonds between a metal and a nonmetal are often ionic. Some compounds include both kinds of bonding. Polyatomic ions such as OH−, NO3−, and NH4+ have polar covalent bonds inside the ion. They form ionic compounds when they combine with ions of the opposite charge. Potassium nitrate, KNO3, is one example. It contains K+ and NO3−, so the attraction between those ions is ionic, while the N–O bonds inside nitrate are covalent.

Polar covalent bonds create partial charges, written as δ+ and δ−. The more electronegative atom pulls the electrons closer, so one end of the bond becomes partially negative and the other becomes partially positive. This charge separation creates a bond dipole moment, symbolized by μ. A dipole is shown as a vector, or arrow, that points from the less electronegative atom toward the more electronegative atom. A small plus sign marks the positive end. A longer arrow means a larger electronegativity difference.

A whole molecule can also have a net dipole moment. That depends on both bond polarity and molecular shape. The dipole moment of the molecule is found by adding the bond moments in three-dimensional space. For diatomic molecules, there is only one bond, so the bond dipole sets the molecular polarity. Homonuclear diatomic molecules such as Br2 and N2 have no electronegativity difference, so their dipole moment is zero. Heteronuclear molecules such as CO have a small dipole moment, and HF has a larger one because its electronegativity difference is larger.

Molecular geometry can make polar bonds cancel. CO2 is linear, so its two polar C=O bond moments point in opposite directions and cancel. The molecule is nonpolar even though its bonds are polar. Water is different. Its Lewis structure shows two bonds to oxygen, and each bond has a nonzero dipole moment. Because the molecule is bent, the bond moments do not cancel. Water therefore has a net dipole moment and is a polar molecule.

How Bond Polarity Shapes Molecular Dipoles

how-bond-polarity-shapes-molecular-dipoles

types of chemical bonds

Chemical Bonding and Bond Properties

Chemical bonding explains how atoms and ions join to form molecules and compounds. American chemist Gilbert N. Lewis pioneered chemical bonding theory with the Lewis model. This model helps explain why bonds form, why some are stronger than others, and why compounds have fixed formulas like H2O instead of H4O. Ionic bonding involves ions, which are atoms or molecules with an electrical charge. A cation is a positive ion formed when a neutral atom loses one or more electrons from its valence...

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Predicting Ionic Stability with Lattice Energy

Lattice energy helps explain why ionic compounds are stable. It measures the strength of attraction between positive and negative ions in a crystal. In one common definition, lattice energy is the energy required to separate one mole of an ionic solid into gaseous ions, so it has a positive value. Another definition uses the opposite sign and describes the energy released when gaseous ions form a lattice. When checking data, it is important to confirm which convention is being used. In either...

lewis symbols and the octet rule

Valence Electrons, Lewis Symbols, and Bonding

Chemical bonds form when atoms or ions interact in ways that lower the potential energy of a molecule. Gilbert N. Lewis created a simple model to show bond formation using valence electrons, the electrons in the outer shell. In this model, electrons are shared or transferred to help atoms reach a stable electron configuration. The Lewis model helps describe two common bond types. An ionic bond forms when electrons move from a metal to a nonmetal. A covalent bond forms when two nonmetals share...

electronegativity

Electronegativity and Polar Bonds

Electronegativity helps explain why some covalent bonds are nonpolar and others are polar covalent. It is a measure of how strongly an atom attracts shared electrons toward itself. That pull controls how electron density is distributed in a bond. Linus Pauling proposed the first electronegativity values by studying bond energies in heteronuclear molecules such as hydrogen fluoride. He expected the bond energy of HF to be about the average of the bond energies of H2 and F2, or 296 kJ/mol. The...

ionic bonding and electron transfer

Ionic Compounds and Crystal Lattices

Ionic compounds form when positive and negative ions attract each other. A cation is a positive ion, and it forms when an atom loses one or more valence electrons. An anion is a negative ion, and it forms when an atom gains one or more valence electrons. Compounds made of these ions are called ionic compounds, or salts, and the force between them is an ionic bond. The properties of ionic solids help show how strong this attraction is. They usually form rigid, brittle crystals and have high...

trends in lattice energy: ion size and charge

trends-in-lattice-energy-ion-size-and-charge

Lattice Energy Patterns in Ionic Solids

Lattice energy shows how strongly ions hold an ionic solid together. It is the energy required to separate one mole of a solid into its gaseous ions. For sodium chloride, this process requires 769 kJ per mole. The opposite convention may also be used, where lattice energy is the energy released when gaseous ions form the solid. In either case, a larger magnitude means a more stable ionic compound. For ionic crystals, lattice energy follows a pattern based on charge and ion size. The...

covalent bonding and lewis structures

Shared Electrons in Covalent Molecules

Covalent molecules form when atoms share electrons instead of transferring them. This bonding usually happens between nonmetal atoms with similar tendencies to attract electrons. Because the atoms pull on the electrons in a shared way, the bond is held together by mutual attraction. Covalent compounds often have physical properties that differ from ionic compounds. The attraction between neutral molecules is weaker than the attraction between charged ions. As a result, many covalent compounds...

bond polarity, dipole moment, and percent ionic character

Bond polarity depends on electronegativity, the ability of an atom to attract shared electrons. The absolute value of the electronegativity difference, or ΔEN, gives a rough guide to bond type. When the difference is very small or zero, the bond is covalent and nonpolar. When it is larger, the bond may be polar covalent or ionic. Examples show how this works in real compounds. H–H has a ΔEN of 0, so it is nonpolar. H–Cl has a ΔEN of 0.9, so it is polar covalent. Na–Cl has a ΔEN of 2.1, so it...

lewis structures of molecular compounds and polyatomic ions

lewis-structures-of-molecular-compounds-and-polyatomic-ions

Drawing Lewis Structures with Valence Electron Counts

Drawing Lewis structures starts with counting valence electrons and building the atom arrangement step by step. Valence electrons are the outer-shell electrons that help show how atoms bond. For ions, a positive charge means one electron is removed for each plus sign, and a negative charge means one electron is added for each minus sign. The next step is to sketch the skeleton structure. The least electronegative atom usually goes in the center, while hydrogen is almost never central. Fluorine...

resonance

Resonance Forms in Lewis Structures

Resonance forms in Lewis structures help explain molecules and ions that cannot be shown correctly with just one drawing. In nitrite ion, NO2−, the Lewis structure can be drawn in two ways. The N-O and N=O bonds switch positions in the two drawings, but the atoms stay in the same arrangement. If nitrite really had one single bond and one double bond, the two bond lengths should be different. A double bond is shorter and stronger than a single bond between the same atoms. Experiments show that...

formal charges

Lewis Structures with Formal Charge

Lewis structures can sometimes show more than one reasonable arrangement for a molecule or polyatomic ion. Formal charge helps chemists choose the best Lewis structure when that happens. It is a useful way to compare possible structures in chemistry. Formal charge is the hypothetical charge an atom would have if bonding electrons were shared evenly between the atoms. It can also be found by starting with the valence electrons of the neutral atom, subtracting the nonbonding electrons, and then...

exceptions to the octet rule

Octet Rule Exceptions in Lewis Structures

Some covalent molecules do not follow the octet rule in their Lewis structures. Their central atoms can fall into three groups: odd-electron molecules, electron-deficient molecules, and hypervalent molecules. These cases show why a Lewis structure may not always give every atom eight valence electrons. Odd-electron molecules have an odd number of valence electrons, so one electron remains unpaired. Molecules with an odd number of electrons are called radicals. Nitric oxide, NO, is one example,...

bond energies and bond lengths

How Bond Energy Predicts Reaction Heat

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bonding in metals

Electron Sea Model in Metals

Electron sea model explains how metallic bonding holds metals together. In this model, most metal atoms do not have enough valence electrons to form ionic or covalent bonds in the usual way. Their valence electrons are held loosely because metals have low electronegativity, and their ionization energy is low, so electrons are removed easily. When a metal atom loses these outer electrons, it becomes a positively charged metal ion. The freed electrons form a delocalized electron cloud around...

key terms and concepts

Learn how electronegativity, bond dipoles, and molecular shape determine whether a bond or molecule is polar, using examples like HCl, CO2, and water.

How Bond Polarity Shapes Molecular Dipoles | JoVE K12

chemistry

JoVE Core 화학은 간결하고 이해하기 쉬운 애니메이션을 통해 일반 화학 개념을 설명합니다. 또한, 과학자가 직접 고전실험과 연구실험을 진행하는 실사 영상을 제공합니다.

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Ohio’s Learning Standards and Model Curriculum

Physical Science

Study Of Matter

Bonding and compounds

Structure And Properties Of Matter

Chemical bonding

Tennessee Academic Standards

High School

Matter and Its Interactions

CHEM1.PS1.13

CHEM1.PS1.14

Virginia  Standards of Learning

HIgh School

CH.3

CH.3.d

Physics

PH.9

PH.9.e

Alabama Course of Study Science

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Motion and Stability: Forces and Interactions

9-12.C.2.2.c

9-12.C.2.2.e

Texas Essential Knowledge and Skills

Chemistry and Physics

IPC.7

IPC.7.A

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New York State Science Learning Standards

HS. Structure and Properties of Matter

HS-PS1-3.

HS. Chemical Reactions

HS-PS1-2.

Scientific Laws and Theories

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The Scientific Method

Chemistry is an empirical science. Scientists often pose questions to understand the chemistry in everyday life and seek answers to these questions. To ...

Classifying Matter by State

Chemistry is the study of matter and the changes it undergoes. Matter is anything that has mass and occupies space. Matter is all around us; the air, ...

Classifying Matter by Composition

Matter: Pure Substances and Mixtures
According to its composition, the matter can be classified into two broad categories &mdash; pure substances and ...

The Atomic Theory of Matter

The earliest recorded discussion of the basic structure of matter comes from ancient Greek philosophers. Leucippus and Democritus argued that all matter ...

Subatomic Particles

Dalton was only partially correct about the particles that make up matter. All matter is composed of atoms, and atoms are composed of three smaller ...

Elements: Chemical Symbols and Isotopes

A chemical symbol is an abbreviation used to indicate an element or an atom of an element. For example, the symbol for mercury is Hg. The same symbol is ...

Use models to explain how the scientific understanding of atomic structure has evolved.

PS.Chm.1.1

Radioactivity and Nuclear Equations

Nuclear chemistry is the study of reactions that involve changes in nuclear structure. The nucleus of an atom is composed of protons and, except for ...

Types of Radioactivity

The most common types of radioactivity are &#945; decay, &#946; decay, &#947; decay, neutron emission, and electron capture.
Alpha (&#945;) decay is the ...

Nuclear Stability

Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10&#8722;15 meters, a nucleus is ...

Nuclear Binding Energy

The difference between the calculated and experimentally measured masses is known as the mass defect of the atom. In the case of helium-4, the mass defect ...

Radioactive Decay and Radiometric Dating

Radioactivity is a spontaneous disintegration of an unstable nuclide and is a random process, as all the nuclei in the sample do not decay simultaneously. ...

Nuclear Fission

Many heavier elements with smaller binding energies per nucleon can decompose into more stable elements that have intermediate mass numbers and larger ...

Nuclear Power

Controlled nuclear fission reactions are used to generate electricity. Any nuclear reactor that produces power via the fission of uranium or plutonium by ...

Nuclear Fusion

The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process ...

Nuclear Transmutation

Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with ...

Use models to compare nuclear reactions including alpha decay, beta decay and gamma decay; nuclear fusion and nuclear fission.

PS.Chm.1.2

Atomic Orbitals

An atomic orbital represents the three-dimensional regions in an atom where an electron has the highest probability to reside. The radial distribution ...

The Pauli Exclusion Principle

The arrangement of electrons in the orbitals of an atom is called its electron configuration. We describe an electron configuration with a symbol that ...

The Energies of Atomic Orbitals

In an atom, the negatively charged electrons are attracted to the positively charged nucleus. In a multielectron atom, electron-electron repulsions are ...

The Aufbau Principle and Hund's Rule

To determine the electron configuration for any particular atom, we can build the structures in the order of atomic numbers. Beginning with hydrogen, and ...

electron-configuration-of-multielectron-atoms

Electron Configuration of Multielectron Atoms

The alkali metal sodium (atomic number 11) has one more electron than the neon atom. This electron must go into the lowest-energy subshell available, the ...

Use models to explain how electrons are distributed in atoms.

PS.Chm.1.3

Periodic Classification of the Elements

The periodic table arranges atoms based on increasing atomic number so that elements with the same chemical properties recur periodically. When their ...

The Periodic Table

As early chemists discovered more elements, they realized that various elements could be grouped by their similar chemical behaviors. One such grouping ...

Atomic Mass

Atoms &mdash; and the protons, neutrons, and electrons that compose them &mdash; are extremely small. For example, a carbon atom weighs less than 2 ...

Molar Mass

The identity of a substance is defined not only by the types of atoms or ions it contains but by the quantity of each type of atom or ion. For example, ...

Use the Periodic Table as a model to predict the relative properties of elements based on the pattern of valence electrons in the outermost energy levels of atoms.

PS.Chm.2.1

atomic-radii-and-effective-nuclear-charge

Atomic Radii and Effective Nuclear Charge

The elements in groups of the periodic table exhibit similar chemical behavior. This similarity occurs because the members of a group have the same number ...

Ionic Radii

Ionic radius is the measure used to describe the size of an ion. A cation always has fewer electrons and the same number of protons as the parent atom; it ...

Ionization Energy

The amount of energy required to remove the most loosely bound electron from a gaseous atom in its ground state is called its first ionization energy ...

Electron Affinity

The electron affinity (EA) is the energy change for adding an electron to a gaseous atom to form an anion (negative ion).



This process can be either ...

Construct an explanation to infer the atomic size, reactivity, electronegativity, and ionization energy of an element based on its position in the Periodic Table.

PS.Chm.2.2

Types of Chemical Bonds

Chemical bonding theories were pioneered by American chemist Gilbert&#xA0;N. Lewis. He developed a model called the Lewis model to explain the type and ...

Lewis Symbols and the Octet Rule

Chemical bonds are complex interactions between two or more atoms or ions, which reduce the potential energy of the molecule. Gilbert N. Lewis developed a ...

Ionic Bonding and Electron Transfer

Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence ...

The Born-Haber Cycle

Lattice Energy&#xA0;

An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a ...

Trends in Lattice Energy: Ion Size and Charge

An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure ...

Covalent Bonding and Lewis Structures

Compared to ionic bonds, which results from the transfer of electrons between metallic and nonmetallic atoms, covalent bonds result from the mutual ...

Electronegativity

Whether a bond is nonpolar or polar covalent is determined by a property of the bonding atoms called electronegativity.&#xA0;

Electronegativity values of ...

Bond Polarity

The absolute value of the difference in electronegativity (&Delta;EN) of two bonded atoms provides a rough measure of the polarity to be ...

Lewis Structures of Molecular Compounds and Polyatomic Ions

To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:


	Determine the ...

Resonance

The Lewis structure of a nitrite anion (NO2&minus;) may actually be drawn in two different ways, distinguished by the locations of the N-O and N=O ...

Formal Charges

In some cases, there are seemingly more than one valid Lewis structures for molecules and polyatomic ions. The concept of formal charges can be used to ...

Exceptions to the Octet Rule

Many covalent molecules have central atoms that do not have eight electrons in their Lewis structures. These molecules fall into three categories:


	...

Analyze and interpret data to explain the mechanisms and properties of the two main types of intramolecular (ionic and covalent) bonds.

Analyze the structure of atoms and isotopes.

How Bond Polarity Shapes Molecular Dipoles

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