Name: elementary steps in reaction mechanisms
Uploaded: 2020-09-24T15:06:50.000Z
Duration: 3 min 6 s
Channel: JoVE

K12 Standards

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

North Carolina K-12 Science Standard Course of Study

9-12

Chemistry

Matter and its Interactions

PS.Chm.5.1

Reaction Mechanisms

化学反応は、多くの場合、反応物と生成物を示す全体的にバランスの取れた化学方程式で表されます。
しかし、実際の反応はもっと複雑で、複数のステップで起こることが多いです。例えば、この一酸化窒素と水素形成窒素ガスおよび水との反応は、3つの異なる連続したステップで行われます。これらのステップを反応メカニズムと呼びます。
反応メカニズムの各ステップは基本反応と呼ばれ、反応する種間の結合の切断や形成などの相互作用を表します。
二酸化二窒素や亜酸化窒素などの特定の分子は、ある基本ステップで形成され、別のステップで消費されます。このような種は反応中間体と呼ばれます。
反応中間体は、素反応の低エネルギー生成物です。それらはしばしば短命であり、それは製品混合物中にそれらが存在しないことを説明しています。反応中間体は、活性化錯体と同じではありません。活性化錯体は、反応物の生成物への変換中にのみ存在する高エネルギー遷移状態です。 
基本ステップを組み合わせると、全体的な化学反応の方程式が得られます。ここでは、反応中間体が排除されるため、全体的な化学方程式に現れません。
異なる基本反応は、さまざまな速度で進行する可能性があります。最も遅い基本ステップが全体の反応速度を決定します。ここで、二酸化二窒素と水素ガスとの反応が律速ステップです。
素反応は、反応する分子の数や分子性によって、一般的に3つのタイプに分類できます。
単分子反応では、単一の反応分子が1つ以上の生成物に変化します。二分子反応では、2つの異なる分子が反応します。三分子反応は、非常にまれですが、3つの個々の分子が反応して中間体または生成物を生成します。
実験的に決定される全体的な化学反応の速度則とは異なり、素反応の速度則は、それらの反応物の化学量論的係数から予測できます。要するに、素反応の分子性は、素ステップの全体的な反応順序に対応します。
したがって、単分子反応はしばしば一次反応であり、二分子反応は二次反応であり、三分子反応は二次反応です。
反応メカニズムと反応速度論を理解することは、化学者が化学反応を特定し、最適化するのに役立ちます。

反応メカニズム

化学反応は多くの場合、2つ以上の異なる反応が連続して起こり、段階的に進行します。化学平衡式は反応種と生成種を含むが、反応がどのようにして起こるのか、分子レベルでの詳細はわかりません。一方、反応機構（または反応経路）は、反応がどのようにして起こるのかを段階的に詳細に示したものです。
 例えば、オゾンの分解は、2つのステップからなるメカニズムに従っているように見えます。
 <img alt="Eq1" src="/files/ftp_upload/11381/11381_Equation_1.png" style="text-align: center; height: 70px;" />
 反応機構を構成する各ステップを素反応と呼びます。これらの素反応は、ステップ式で表されるように順番に起こり、それらを合計すると、全体の反応を表す平衡化学方程式が得られます。
 <img alt="Eq2" src="/files/ftp_upload/11381/11381_Equation_2.png" style="text-align: center; height: 50px;" />
 第1ステップで生成された酸素原子は第2ステップで消費され、全体の反応では生成物として現れないことに注意する必要があります。このように、ある段階で生成され、次の段階で消費される化学種を「反応中間体」と呼びます。
 全体の反応式では、2つのオゾン分子が反応して3つの酸素分子を生成するように見えるが、実際の反応メカニズムでは、2つのオゾン分子が直接衝突して反応するわけではありません。実際には、1つのO3が分解してO2と酸素原子を生成し、続いて2つ目のO3分子が酸素原子と反応することでさらに2つのO2分子を生成します。
 全体の反応を表す化学平衡式とは異なり、素反応式は詳細な化学変化を直接表しています。素反応式では、実際に結合の切断や生成を行っている反応物と、生成物が含まれます。したがって、素反応における反応速度則は、その化学平衡式から直接導き出すことができます。しかし、素反応が組み合わさった化学反応の場合はそうはいかず、実験によってのみ確実に反応速度を決定することができます。
 単分子の素反応
 素反応における分子性とは、反応種（原子、分子、イオン）の数を指します。例えば、単分子反応では、1つの反応物を反応させて1つ以上の分子の生成物ができます。
 <img alt="Eq3" src="/files/ftp_upload/11381/11381_Equation_3.png" style="text-align: center; height: 50px;" />
 単分子反応の速度則は一次であり、"反応速度" = k [A]です。
 単分子反応は、複雑な反応機構における素反応の一つである場合があります。例えば、(O3 (g) → O2 (g) + O)という反応は、2段階の反応機構の一部として起こる単分子の素反応を示しています。しかし、単分子反応の中には、1段階の反応機構の唯一のステップとなるものもあります。(つまり、全体の反応が一つの素反応で表される場合。) 例えば、シクロブタン(C4H8)が気相でエチレン(C2H4)に分解される現象は、次の反応式で表されます。
 <img alt="Eq3A" src="/files/ftp_upload/11381/11381_Equation_3A.png" style="text-align: center; height: 50px;" />
 この式は反応全体を表し、単分子の素反応を記述しています。この式から予測される速度則は、素反応であると仮定すると、実験的に得られた反応全体の速度則と同じになり、一次の挙動を示します。
 <img alt="Eq4" src="/files/ftp_upload/11381/11381_Equation_4.png" style="text-align: center; height: 70px;" />
 このように観察された速度則と予測された速度則が一致したことから、提案された単分子の1段階プロセスがブタジエン反応の合理的なメカニズムであることが示されました。
 二分子の素反応
 二分子反応は、2つの反応種を含む。例えば、以下のようなものです。
 <img alt="Eq5" src="/files/ftp_upload/11381/11381_Equation_5.png" style="text-align: center; height: 70px;" />
 2つの反応分子が異なる1つ目のタイプでは、速度則はAで1次、Bで1次（全体では2次）となります。
 <img alt="Eq6" src="/files/ftp_upload/11381/11381_Equation_6.png" style="text-align: center; height: 50px;" />
 2つの同じ分子が衝突して反応する2つ目のタイプでは、速度則はAの2次になります。
 <img alt="Eq7" src="/files/ftp_upload/11381/11381_Equation_7.png" style="text-align: center; height: 50px;" />
 化学反応の中には、1つの二分子素反応からなるメカニズムで起こるものがあります。その一例が、二酸化窒素と一酸化炭素の反応です。
 <img alt="Eq8" src="/files/ftp_upload/11381/11381_Equation_8.png" style="text-align: center; height: 50px;" />
 また、多段階の反応機構のステップとして、2分子の素反応が関与することもあります。原子状酸素とオゾンの反応は、2段階のオゾン分解メカニズムにおける第2段階にあたます。
 <img alt="Eq9" src="/files/ftp_upload/11381/11381_Equation_9.png" style="text-align: center; height: 50px;" />
 三分子の素反応
 3つの原子、分子、イオンが同時に衝突するのが「3分子素反応」です。3つの粒子が同時に衝突する確率は非常に低いため、3分子素反応は一般的ではありません。しかし、いくつかの既に知られた3分子素反応があります。一酸化窒素と酸素の反応には、3分子素反応が関与したステップが含まれています。
 <img alt="Eq10" src="/files/ftp_upload/11381/11381_Equation_10.png" style="text-align: center; height: 70px;" />
 同様に、一酸化窒素と塩素の反応には、3分子素反応が関与したステップが含まれていると考えられています。
 <img alt="Eq11" src="/files/ftp_upload/11381/11381_Equation_11.png" style="text-align: center; height: 70px;" />
 多段階の反応機構では、素反応の1つが他のステップにおける素反応よりも著しく遅いことがよくあります。反応は最も遅いステップよりも速く進むことはできないため、このステップは全体の反応が起こる速度を制限します。そのため、最も遅い基本ステップは、反応の律速段階と呼ばれます。
 上記の文章は以下から引用しました。 <a href="https://openstax.org/books/chemistry-2e/pages/12-6-reaction-mechanisms">Openstax, Chemistry 2e, 12.6: Reaction Mechanisms.</a>

化学反応は、多くの場合、2つ以上の異なる反応が順番に起こるという段階的な方法で発生します。バランスの取れた方程式は...

Education

JoVE Core

化学

Chemical Kinetics

化学反応速度論

KEY TERMS AND CONCEPTS

主要用語と概念

elementary steps in reaction mechanisms

Chemical reactions can happen in steps, and a balanced equation does not show the full path at the molecular level. A reaction mechanism, also called a reaction path, gives the step-by-step process that explains how reactants become products. The decomposition of ozone is one example of a reaction that can be described by a sequence of steps.

Each step in a mechanism is an elementary reaction. These elementary reactions happen in order, and when they are added together, they give the balanced equation for the overall reaction. In the ozone example, an oxygen atom is made in the first step and used up in the second step, so it does not appear in the final equation. A species made in one step and used up in a later step is called a reaction intermediate.

The overall equation may show two ozone molecules forming three oxygen molecules, but the mechanism shows that the two ozone molecules do not react directly with each other. Instead, one O3 molecule breaks down to form O2 and an oxygen atom. Then a second O3 molecule reacts with that oxygen atom to make two more O2 molecules. This is why elementary reaction equations give a more direct picture of bond breaking and bond making than the overall equation does.

For an elementary reaction, the rate law can often be written directly from the balanced equation for that step. For most chemical reactions, the rate law must be found by experiment. That is why elementary reactions are useful when chemists build a mechanism that matches the observed behavior of a reaction.

Elementary reactions are described by molecularity, which is the number of reactant species in the step. A unimolecular reaction has one reactant species and forms one or more products. Its rate law is first order, written as rate = k[A]. A unimolecular step may be part of a larger mechanism, such as O3(g) → O2(g) + O in ozone decomposition. Some unimolecular reactions are also the whole reaction, not just one step. The gas-phase decomposition of cyclobutane, C4H8, to ethylene, C2H4, is one example, and its first-order experimental rate law agrees with the rate law predicted for an elementary single-step process.

A bimolecular reaction involves two reactant species. If the two reactants are different, the rate law is first order in A and first order in B, for a second-order overall rate. If the two reacting molecules are the same, the rate law is second order in A. Some reactions occur by a single bimolecular elementary reaction, such as the reaction of nitrogen dioxide with carbon monoxide. Bimolecular steps can also appear in multistep mechanisms, including the reaction of atomic oxygen with ozone in ozone decomposition.

A termolecular reaction involves the simultaneous collision of three atoms, molecules, or ions. These reactions are uncommon because three particles colliding at the same time is very unlikely. Still, a few termolecular elementary reactions are known. The reaction of nitric oxide with oxygen and the reaction of nitric oxide with chlorine both appear to involve termolecular steps.

In many multistep mechanisms, one elementary step is much slower than the others. A reaction cannot proceed faster than its slowest step, so that step controls the overall rate. This slowest step is called the rate-limiting step, or rate-determining step.

Elementary Steps in Reaction Mechanisms

reaction rate

Measuring Reaction Rates

Measuring reaction rates shows how fast reactants are used up or products are formed over time. The rate of reaction is the change in the amount of a reactant or product per unit time. Because of that, scientists measure how a property changes as the reaction proceeds and connect that change to reactant or product amounts. For reactions that make or use a gas, the rate can be followed by changes in volume or pressure. A rate expression is the mathematical way to write how concentration changes...

measuring reaction rates

Tracking Reaction Kinetics with Light and Pressure

Reaction kinetics can be tracked with polarimetry, spectrometry, and pressure measurements. These methods let scientists follow a reaction without disturbing the sample. They also help determine how reactant or product concentrations change over time. Polarimetry is used for optically active substances. These substances rotate the plane of polarized light, which is called optical rotation. The effect comes from molecular structure. Normal monochromatic light is unpolarized, but after it passes...

concentration and rate law

Reaction Order from Concentration

Reaction order from concentration shows how reactant amounts affect reaction rate. Rate laws, also called differential rate laws or rate equations, are mathematical expressions that connect reaction rate with the concentrations of reactants. For a generic reaction a A + b B → products, the rate law can be written using the reactant concentrations [A] and [B] and a rate constant k. In a rate law, k is the rate constant for one specific reaction at one specific temperature. The exponents m and n...

determining order of reaction

Finding Rate Law from Initial Rates

Rate laws connect the speed of a chemical reaction to the concentration of its reactants. The rate constant, k, and the reaction orders are not taken from the chemical equation. They are found experimentally by watching how the rate changes when the reactant concentrations change. One common way to do this is the method of initial rates. In this method, several trials are run with different starting concentrations. The measured rates are then compared to determine the reaction orders and,...

the integrated rate law: the dependence of concentration on time

the-integrated-rate-law-the-dependence-of-concentration-on-time

Reading Reaction Progress with Integrated Laws

Integrated rate laws connect reaction concentration to time. They help show how much reactant or product is present after a certain period. They can also help estimate how long a reaction must run to reach a given extent. A common use is finding how long radioactive material must be stored before its radioactivity drops to a safe level. These equations come from the differential rate law after it is integrated with respect to time. For a first-order reaction, where rate = k[A], the integrated...

half-life of a reaction

Reaction Half-Life in Kinetics

Reaction half-life is the time needed for half of a reactant to be consumed. After each half-life, half of the remaining reactant is used up. A hydrogen peroxide decomposition example shows this pattern clearly. The concentration drops from 1.000 M to 0.500 M in the first 6.00 hours, then to 0.250 M in the next 6.00 hours, and then to 0.125 M in the third period. Each later 6.00-hour interval removes half of what is left. For first-order reactions, the half-life does not depend on the reactant...

temperature dependence on reaction rate

Collision Theory and Reaction Speed

Collision theory explains why reaction speed depends on how particles collide. Atoms, molecules, or ions must come close together before they can react. The theory says the reaction rate depends on the collision rate, the orientation of the colliding species, and whether the collision has enough energy for bonds to change. A gas-phase reaction between carbon monoxide and oxygen shows why orientation matters. The molecules can collide in more than one way. If the oxygen side of carbon monoxide...

arrhenius plots

Determining Activation Energy from Temperature

The Arrhenius equation links activation energy and the rate constant, k, for chemical reactions. It is written as k = Ae−Ea/RT. In this equation, R is the ideal gas constant with a value of 8.314 J/mol·K, T is the temperature on the kelvin scale, Ea is the activation energy in J/mole, e is the constant 2.7183, and A is the frequency factor. The frequency factor depends on collision frequency and the orientation of reacting molecules. Experimental kinetic data can be used to find the activation...

reaction mechanisms

Chemical reactions can happen in steps, and a balanced equation does not show the full path at the molecular level. A reaction mechanism, also called a reaction path, gives the step-by-step process that explains how reactants become products. The decomposition of ozone is one example of a reaction that can be described by a sequence of steps. Each step in a mechanism is an elementary reaction. These elementary reactions happen in order, and when they are added together, they give the balanced...

rate-determining steps

Reaction Bottlenecks in Chemical Kinetics

Reaction bottlenecks help explain rate-determining steps in multistep reaction mechanisms. In a mechanism with several elementary steps, one step is often much slower than the others. That slowest step is called the rate-limiting step, or rate-determining step. A reaction cannot move faster than its slowest step, so this step controls the overall reaction rate. The idea is like traffic on a four-lane freeway with one lane closed. Cars can only move as fast as the bottleneck allows. In the same...

catalysis

Catalyst Action in Reaction Rates

Catalysts change the rate of a chemical reaction by giving it a faster path. A catalyst increases reaction rate without being consumed during the process. Its effect is often explained with reaction mechanisms and energy diagrams. For an endothermic reaction, the reactants and products start and end at the same energies in both cases. The uncatalyzed path is a one-step mechanism with one transition state. The catalyzed path follows a different mechanism with two transition states and a lower...

enzymes

Enzyme Action and Inhibition

Enzymes are biological catalysts that speed up many reactions in living organisms. They help control cellular metabolism by lowering the activation energy needed for biochemical reactions. When activation energy drops, reaction rates can increase. Enzyme problems can also lead to serious disease. A genetic abnormality that causes G6PD, or glucose-6-phosphate dehydrogenase, deficiency can disrupt the pathway that supplies NADPH to cells. In red blood cells, this can reduce glutathione and...

key terms and concepts

Explore how chemical reactions happen in steps, including elementary reactions, reaction intermediates, molecularity, rate laws, and the rate-limiting step.

Elementary Steps in Reaction Mechanisms | JoVE K12

chemistry

JoVE Core 化学は、簡潔で理解しやすいアニメーションビデオレッスンを使用して、一般的な化学の概念を生き生きとしたものにします。さらに、活動する科学者のビデオでは、現在世界中の実験室で行われている古典的そして独創的な研究・実験をお見せします。

Pennsylvania State Academic Standards

Physical Science

Chemical Reactions

3.2.9-12.D

3.2.9-12.E

Louisiana Student Standards for Science

High School

Matter And Its Interactions

HS-PS1-4

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Interactions Of Matter

Chemical reactions

Virginia  Standards of Learning

HIgh School

CH.7

CH.7.e

Arizona Science Standards

HS.P1

HS.P1U1.3

Alabama Course of Study Science

Matter and Its Interactions: Energy

9-12.C.3.3.b

Next Generation Science Standards

Matter and Its Interactions

HS-PS1-2

HS-PS1-5

HS-PS1-7

Florida Department of Education

SC.912.P.12

SC.912.P.12.12

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

C-PS1-4

C-PS1-5

new-york-state-science-learning-standards

New York State Science Learning Standards

HS. Chemical Reactions

HS-PS1-5.

Scientific Laws and Theories

Scientific Laws

In science, a law is defined as a concise, verbal or mathematical, statement that summarizes a vast number of experimental observations. ...

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

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-dipole-moment-and-percent-ionic-character

Bond Polarity, Dipole Moment, and Percent Ionic Character

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

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:


	...

Bond Energies and Bond Lengths

Stable molecules exist because covalent bonds hold the atoms together. The strength of a covalent bond is measured by the energy required to break it, ...

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

PS.Chm.3.1

Analyze the structure of atoms and isotopes.

Elementary Steps in Reaction Mechanisms

Description

Transcript

Tags

More videos by Standards