Name: transition metals in the periodic table
Uploaded: 2020-09-24T15:06:53.000Z
Duration: 2 min 58 s
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Louisiana Student Standards for Science

High School

Chemistry

Matter And Its Interactions

HS-PS1-2

Properties of Transition Metals

Les métaux de transition sont un groupe d'éléments situés dans le bloc d. Ils sont placés entre les principaux éléments du groupe et exposent caractéristiques uniques, telles que la conductivité électrique, couleurs, dureté, points de fusion élevés et magnétisme. Beaucoup de ces caractéristiques sont attribuées au remplissage des orbitales d.Se déplaçant à travers la période, les électrons sont ajoutés selon le principe Aufbau. Cependant, l'orbitale la plus externe est remplie en premier, avant que l'électron n'entre dans la sous-classe d à quelques exceptions près. Le chrome et le cuivre ont un demi-rempli orbitale car elle est plus énergétiquement favorisé pour avoir un sous-classe d à moitié rempli ou plein.La taille atomique des métaux de transition diminue légèrement sur une période. Lorsque les électrons entrent dans la sous-classe d, le nombre d'électrons de valence à l'extérieur s orbitale reste stable, menant à une charge nucléaire globale constante. En bas de la colonne, la tendance augmente à partir du quatrième à la cinquième période, mais pas en dessous.La 6ème période contient 14 éléments supplémentaires de la série des lanthanides, où les électrons entrent dans la sous-classe(n-2)f avant d'entrer dans la sous-classe d. Électrons situés dans les orbitales f ne protège pas suffisamment les électrons de valence dans l'orbite la plus externe, ce qui entraîne dans une charge nucléaire efficace accrue. Ainsi, les électrons de valence sont attirés plus fortement, conduisant à des rayons atomiques plus petits.Ceci est connu comme la contraction du lanthanide. De même, l'électronégativité des éléments de transition est influencé par sa taille atomique et sa charge nucléaire. En se déplaçant sur une période, il n'augmente que légèrement.En bas de la colonne, l'électronégativité augmente de la quatrième à la cinquième période mais reste constant dans la sixième période. Ceci est attribué à une diminution de la taille atomique et une augmentation de la charge nucléaire. L'énergie d'ionisation des métaux de transition augmente légèrement sur une période.Il est intéressant de noter qu'en bas de la colonne, il est plus élevé pour la 6ème période que pour les 4ème et 5ème périodes. Ici, les électrons de valence sont maintenus plus étroitement lorsque la charge nucléaire augmente avec une augmentation négligeable en taille atomique. Enfin, les métaux de transition peuvent avoir une gamme d'états d'oxydation stables en perdant les électrons orbitaux les plus externes avant les électrons orbitaux d non appariés.Les orbitales d partiellement remplies permettent des états d'oxydation allant de 7 à 1, couleurs caractéristiques, et propriétés magnétiques.

propriétés des métaux de transition

Les métaux de transition sont définis comme les éléments qui ont des orbitales d partiellement remplies. Comme le montre la figure 1, les éléments du bloc d des groupes 3 à 12 sont des éléments de transition. Les éléments du bloc f, qu'on appelle aussi métaux de transition interne (lanthanides et actinides), répondent également à ce critère car l'orbitale d est partiellement occupée avant les orbitales f.
 <img alt="Image1" src="/files/ftp_upload/11454/11454_Image_1.png" style="text-align: center; height: 500px;" />
 Figure 1 : tableau périodique. Les métaux de transition sont situés dans les groupes 3 à 11 du tableau périodique. Les métaux de transition interne se trouvent dans les deux lignes sous le corps du tableau. 
 Les éléments du bloc d sont divisés en la première série de transition (les éléments Sc à Cu), la deuxième série de transition (les éléments Y à Ag) et la troisième série de transition (l'élément La et les éléments Hf à Au). L'actinium, Ac, est le premier membre de la quatrième série de transition, qui comprend aussi Rf à Rg. 
 Les éléments du bloc f sont les éléments Ce à Lu, qui constituent la série des lanthanides (ou série lanthanoïde), et les éléments Th à Lr, qui constituent la série des actinides (ou série actinoïde). Comme le lanthane se comporte beaucoup comme les éléments des lanthanides, il est considéré comme un élément des lanthanides, même si sa configuration électronique en fait le premier membre de la troisième série de transition. De même, le comportement de l'actinium signifie qu'il fait partie de la série des actinides, bien que sa configuration électronique en fait le premier membre de la quatrième série de transition. 
 Les éléments de transition ont de nombreuses propriétés en commun avec d'autres métaux. Ce sont presque tous des solides durs à fusion élevée qui conduisent bien la chaleur et l'électricité. Ils forment facilement des alliages et perdent des électrons pour former des cations stables. En outre, les métaux de transition forment une grande variété de composés de coordination stables, dans lesquels l'atome ou l'ion métallique central agit comme un acide de Lewis et accepte un ou plusieurs doublets d'électrons. De nombreuses molécules et ions différents peuvent donner des doublets libres au centre métallique, servant de bases de Lewis. 
 Propriétés des éléments de transition 
 Les métaux de transition présentent un large éventail de comportements chimiques. Certains métaux de transition sont des agents réducteurs forts, alors que d'autres ont une réactivité très faible. Par exemple, les lanthanides forment tous des cations aqueux 3+ stables. La force motrice de ces oxydations est semblable à celle des métaux alcalino-terreux tels que le Be ou le Mg, formant Be2+ et Mg2+. D'autre part, les matériaux comme le platine et l'or ont des potentiels de réduction beaucoup plus élevés. Leur capacité à résister à l'oxydation en fait des matériaux utiles pour la construction de circuits et de bijoux. 
 Les ions des éléments du bloc d plus légers, tels que Cr3+, Fe3+ et Co2+, forment des ions hydratés colorés qui sont stables dans l'eau. Cependant, les ions de la période juste en dessous d'eux (Mo3+, Ru3+ et Ir2+) sont instables et réagissent facilement avec l'oxygène de l'air. La majorité des ions simples et stables dans l'eau formés par les éléments plus lourds du bloc d42− et  ReO4−. 
 Le ruthénium, l'osmium, le rhodium, l'iridium, le palladium et le platine sont les métaux du platine. Avec difficulté, ils forment des cations simples qui sont stables dans l'eau et, contrairement aux éléments précédents des deuxième et troisième séries de transition, ils ne forment pas d'oxyanions stables. 
 Les éléments des blocs det f réagissent avec les non-métaux pour former des composés binaires ; le chauffage est souvent nécessaire. Ces éléments réagissent avec des halogènes pour former divers halogénures dont le degré d'oxydation varie de +1 à +6. Lors du chauffage, l'oxygène réagit avec tous les éléments de transition, à l'exception du palladium, du platine, de l'argent et de l'or. Les oxydes de ces derniers métaux peuvent être formés à l'aide d'autres réactifs, mais ils se décomposent lors du chauffage. Les éléments du bloc f, les éléments du groupe 3 et les éléments de la première série de transition, à l'exception du cuivre, réagissent avec les solutions aqueuses d'acides, formant ainsi de l'hydrogène gazeux et des solutions des sels correspondants. 
 Les métaux de transition peuvent former des composés avec une large gamme d'états d'oxydation. Certains des états d'oxydation observés des éléments de la première série de transition sont indiqués dans le tableau 1. En se déplaçant de gauche à droite à travers la première série de transition, le nombre de degrés d'oxydation communs augmente d'abord à un maximum vers le milieu du tableau, puis diminue. Les valeurs du tableau sont des valeurs typiques ; il existe d'autres valeurs connues et il est possible de synthétiser de nouveaux ajouts. Par exemple, en 2014, les chercheurs ont réussi à synthétiser un nouvel état d'oxydation de l'iridium (+9). 
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 <td style="color: black; border: 1px solid black; text-align: center;">21Sc </td>
 <td style="color: black; border: 1px solid black; text-align: center;">22Ti </td>
 <td style="color: black; border: 1px solid black; text-align: center;">23V </td>
 <td style="color: black; border: 1px solid black; text-align: center;">24Cr </td>
 <td style="color: black; border: 1px solid black; text-align: center;">25Mn </td>
 <td style="color: black; border: 1px solid black; text-align: center;">26Fe </td>
 <td style="color: black; border: 1px solid black; text-align: center;">27Co </td>
 <td style="color: black; border: 1px solid black; text-align: center;">28Ni </td>
 <td style="color: black; border: 1px solid black; text-align: center;">29Cu </td>
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 Tableau 1. Les métaux de transition de la première série de transition peuvent former des composés avec des états d'oxydation variables. 
 Pour les éléments du scandium au manganèse (la première moitié de la première série de transition), l'état d'oxydation le plus élevé correspond à la perte de tous les électrons dans les orbitales s et d de leurs couches de valence. L'ion titane(IV), par exemple, se forme lorsque l'atome de titane perd ses deux électrons 3d et ses deux électrons 4s. Ces états d'oxydation les plus élevés sont les formes les plus stables du scandium, du titane et du vanadium. Cependant, il n'est pas possible de continuer à enlever tous les électrons de valence des métaux à mesure que nous continuons dans la série. On sait que le fer forme des états d'oxydation de +2 à +6, le fer(II) et le fer(III) étant les plus courants. La plupart des éléments de la première série de transition forment des ions avec une charge de 2+ ou 3+ qui sont stables dans l'eau, bien que ceux des premiers membres de la série puissent être facilement oxydés par l'air. 
 Les éléments de la deuxième et de la troisième série de transition sont généralement plus stables dans les états d'oxydation plus élevés que les éléments de la première série. En général, le rayon atomique augmente en descendant dans un groupe, ce qui fait que les ions de la deuxième et de la troisième série sont plus grands que ceux de la première série. Il est plus facile d'enlever les électrons des orbitales situées plus loin du noyau que d'enlever les électrons proches du noyau. Par exemple, le molybdène et le tungstène, des membres du groupe 6, sont limités principalement à un état d'oxydation de +6 en solution aqueuse. Le chrome, le membre le plus léger du groupe, forme des ions Cr3+ stables dans l'eau et, en l'absence d'air, des ions Cr2+ moins stables. Le sulfure ayant l'état d'oxydation le plus élevé pour le chrome est Cr2S3, qui contient l'ion Cr3+. Le molybdène et le tungstène forment des sulfures dans lesquels les métaux présentent des états d'oxydation de +4 et +6. 
 La grande variété des propriétés présentée par les métaux de transition est due à leurs couches de valence complexes. Contrairement à la plupart des métaux du groupe principal pour lesquels un état d'oxydation est normalement observé, la structure de la couche de valence des métaux de transition signifie qu'ils sont présents généralement dans plusieurs états d'oxydation stables différents. En outre, les transitions d'électrons dans ces éléments peuvent correspondre à l'absorption des photons dans le spectre électromagnétique visible, conduisant à des composés colorés. En raison de ces comportements, les métaux de transition présentent une chimie riche et fascinante. 
 Ce texte est adapté de <a href="https://openstax.org/books/chemistry-2e/pages/19-1-occurrence-preparation-and-properties-of-transition-metals-and-their-compounds"> Openstax, Chimie 2e, Chapitre 19.1 Présence, préparation et propriétés des métaux de transition et de leurs composés. </a>

Propriétés des métaux de transition

Les métaux de transition sont définis comme les éléments dont les orbitales d sont partiellement remplies. Comme le montre la figure 1, les éléments du bloc d des groupes 3 à 12 sont ...

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Transition Metals and Coordination Complexes

Métaux de transition et complexes de coordination

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KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

transition metals in the periodic table

Transition metals are the d-block elements and the inner transition metals in the f-block. They are defined by partially filled d orbitals. In the periodic table, the transition elements are in groups 3 through 11, and the inner transition metals appear in the two rows below the main body of the table.

The d-block is often grouped into transition series. The first transition series runs from Sc through Cu. The second series runs from Y through Ag. The third series includes La and Hf through Au, and the fourth series begins with Ac and continues through Rg. The f-block includes Ce through Lu, which make up the lanthanide series, and Th through Lr, which make up the actinide series. Lanthanum and actinium behave like the lanthanides and actinides, so they are included with those series even though their electron configurations place them at the start of the third and fourth transition series.

Transition metals share several common metal properties. Most are hard, high-melting solids that conduct heat and electricity well. They also form alloys easily and lose electrons to make stable cations. Another major feature is their ability to form stable coordination compounds, where the metal atom or ion acts as a Lewis acid and accepts electron pairs from Lewis bases such as molecules or ions with lone pairs.

These elements show a wide range of chemical behavior. Some transition metals are strong reducing agents, while others are much less reactive. The lanthanides, for example, form stable 3+ aqueous cations, and this oxidation is similar in driving force to the formation of Be2+ and Mg2+ by alkaline earth metals. At the other extreme, platinum and gold have high reduction potentials, so they resist oxidation and are useful in circuits and jewelry.

Ion stability also changes across the d-block. Lighter ions such as Cr3+, Fe3+, and Co2+ often form colorful hydrated ions that remain stable in water. The next heavier ions, such as Mo3+, Ru3+, and Ir2+, are unstable and react quickly with oxygen in air. For the heavier d-block elements, many of the water-stable simple ions are oxyanions, such as MoO4 2− and ReO4−. Ruthenium, osmium, rhodium, iridium, palladium, and platinum are called the platinum metals. They form simple cations only with difficulty, and they do not form stable oxyanions like the earlier elements in the second and third transition series.

Transition metals and inner transition metals also react with nonmetals to form binary compounds, and heating is often needed. They react with halogens to make halides in oxidation states from +1 to +6. When heated, oxygen reacts with all transition elements except palladium, platinum, silver, and gold. The oxides of those metals can be made by other reactions, but they break down when heated. The f-block elements, group 3 elements, and the first transition series except copper react with aqueous acids to form hydrogen gas and the matching salts.

A key reason transition metals are so versatile is that they can form compounds in many oxidation states. In the first transition series, scandium through manganese show a rise in the number of common oxidation states, with a maximum near the middle of the series, and then the number falls again. For scandium through manganese, the highest oxidation state usually comes from removing all valence s and d electrons. Titanium(IV), for example, forms when titanium loses its two 3d and two 4s electrons. Iron can form oxidation states from +2 to +6, but +2 and +3 are the most common. Most first-series transition metals form 2+ or 3+ ions that are stable in water, although the early members are easily oxidized by air.

The second and third transition series are usually more stable in higher oxidation states than the first series. Their larger atomic radius makes electron removal easier because the electrons are farther from the nucleus. For example, molybdenum and tungsten, both group 6 elements, are mostly limited to +6 in aqueous solution. Chromium, the lightest member of the group, forms stable Cr3+ ions in water and less stable Cr2+ ions when air is absent. The highest chromium sulfide is Cr2S3, which contains Cr3+, while molybdenum and tungsten form sulfides with +4 and +6 oxidation states.

The many properties of transition metals come from their complex valence shells. Unlike most main group metals, which usually show one oxidation state, transition metals often appear in several stable oxidation states. Their electron transitions can also absorb visible light, which gives many of their compounds color. These features make transition metal chemistry especially varied and important.

Transition Metals in the Periodic Table

properties of transition metals

Transition metals are the d-block elements and the inner transition metals in the f-block. They are defined by partially filled d orbitals. In the periodic table, the transition elements are in groups 3 through 11, and the inner transition metals appear in the two rows below the main body of the table. The d-block is often grouped into transition series. The first transition series runs from Sc through Cu. The second series runs from Y through Ag. The third series includes La and Hf through...

coordination compounds and nomenclature

How Transition Metal Complexes Are Named

Transition metal complexes are named by following rules for ligands, metal ions, and oxidation state. These compounds form when a central metal ion or atom, often a transition metal or inner transition metal, accepts electron pairs from ligands. A ligand is a Lewis base that can be an atom, molecule, or ion with one or more lone pairs to donate. In these complexes, the bond is a coordinate covalent bond. That means both electrons in the bond come from the donor, such as ammonia, and are...

metal-ligand bonds

Coordination Complexes and Chelation

Coordination complexes form when a metal ion bonds to ligands. These compounds appear in familiar examples such as hemoglobin in blood, chlorophyll in green plants, vitamin B-12, and the catalyst used to make polyethylene. Transition metal ions are especially likely to form these complexes. In a coordination complex, the metal acts as a Lewis acid. The ligand acts as a Lewis base and donates both electrons in the coordinate covalent bond. A ligand can be an atom, molecule, or ion, as long as...

coordination number and geometry

Transition Metal Shapes from Coordination Number

Transition metal complexes are often identified by their coordination number and the shape around the metal ion. The coordination number is the number of donor atoms bonded to the central metal. In many complexes, the most common shapes are octahedral, tetrahedral, and square planar. Coordination number and molecular geometry are linked in a clear pattern. A coordination number of 2 gives a linear shape, as in [Ag(NH3)2]+. A coordination number of 3 gives a trigonal planar shape, as in...

structural isomerism

Linkage and Ionization Isomers

Isomers are different chemical species that share the same chemical formula. In coordination compounds, structural isomerism includes linkage isomers and coordination-sphere isomers. These two forms show how the same atoms can be arranged in different ways around a metal center. Linkage isomers form when a ligand can attach to a transition metal through two different atoms. The cyanide ligand, CN−, can bind through carbon or nitrogen. The thiocyanate ligand, SCN−, can bind through sulfur or...

stereoisomerism

Isomer Shapes in Coordination Complexes

Isomer shapes in coordination complexes can change a compound’s properties even when the chemical formula stays the same. Isomers are different chemical species with the same formula. In transition metal complexes, the atoms stay connected through the same types of bonds, but their arrangement in space can differ. One common form is geometric isomerism. In these complexes, ligands (the ions or molecules attached to the metal) can sit in cis or trans positions. The octahedral [Co(NH3)4Cl2]+ ion...

valence bond theory

Metal Ligand Bonds in Coordination Complexes

Coordination complexes form metal-ligand bonds through valence bond theory. In this model, Linus Pauling explained bonding with hybridization and overlap of atomic orbitals. The central metal atom or ion acts as a Lewis acid. It uses empty orbitals of suitable energy to accept electron pairs from ligands, which act as Lewis bases. These coordinate covalent bonds help explain the color, geometry, and magnetic behavior seen in coordination compounds. The type of hybridization helps determine the...

crystal field theory - octahedral complexes

crystal-field-theory-octahedral-complexes

Octahedral d-Orbital Splitting in Crystal Fields

Crystal field theory explains how ligands affect the d orbitals in transition metal complexes. This electrostatic model helps predict the colors, magnetic behavior, and some structures of coordination compounds. It focuses on the nonbonding electrons on the central metal ion, not on the metal-ligand bonds. In crystal field theory, the metal ion and ligands are treated as very small point charges. Because electrons are negative, electrons donated by the ligands repel the electrons in the...

crystal field theory - tetrahedral and square planar complexes

crystal-field-theory-tetrahedral-and-square-planar-complexes

Crystal Field Splitting in Non-Octahedral Shapes

Crystal field theory also explains d orbital splitting in tetrahedral and square planar complexes. These shapes do not follow the same pattern as an octahedral complex, so the d orbitals respond to ligand placement in different ways. In tetrahedral complexes, the four ligands sit between the axes. None of the d orbitals points directly at the ligands, but the d x2−y2 and d z2 orbitals lie along the Cartesian axes and overlap less with the ligands than the d xy, d xz, and d yz orbitals. The d...

colors and magnetism

Color and Spin in Coordination Complexes

Color in coordination complexes comes from how metal electrons absorb light. When atoms or molecules absorb light at the right frequency, electrons move to higher-energy orbitals. For many main-group atoms and molecules, the absorbed light is ultraviolet and cannot be seen. In coordination compounds, the energy gap between d orbitals often matches visible light, so the compound can absorb and emit colors that the human eye detects. Small changes in orbital energy can cause large shifts in the...

key terms and concepts

Learn where transition metals and inner transition metals are found, why they form many oxidation states, and how their ions, compounds, and colors differ.

Transition Metals in the Periodic Table | JoVE K12

chemistry

JoVE Core Chimie anime les concepts de chimie générale en utilisant des leçons vidéo concises et faciles à comprendre. De plus, nos vidéos de scientifiques à l'action présentent des expériences de recherche, classiques ou insolites, effectuées dans des laboratoires modernes du monde entier.

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

9-12

Physical Geology

Minerals

properties-minerals-hardness-luster-cleavage-streak-crystal-shape

Properties of minerals (hardness, luster, cleavage, streak, crystal shape, fluorescence, flammability, density/specific gravity, malleability)

Minnesota Academic Standards in Science

3.1.1 9C.3.1.1.1

Alabama Course of Study Science

Earth and Space Science

Earth's Systems

9-12.ESS.2.6

Environmental Science

Earth and Human Activity

9-12.EVS.4.7

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

South Carolina College and Career Ready Science Standards

Matter and Its Interactions

C-PS1-2

new-york-state-science-learning-standards

New York State Science Learning Standards

Physical Science

HS. Structure and Properties of Matter

HS-PS2-6.

Georgia Standards of Excellence

SC1.

electron-configuration-and-chemical-properties

Electron Configuration and Chemical Properties

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 ...

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-and-organismal-elements

The Periodic Table And Organismal Elements

Atomic Structure

The Greek philosopher Democritus proposed that everything on Earth is made up of tiny particles called atomos, Greek for &#34;indivisible,&#34; from which ...

Electron Configurations

Electron configurations and orbital diagrams can be determined by applying the Aufbau principle (each added electron occupies the subshell of lowest ...

Electronic Structure of Atoms


An atom comprises protons and neutrons, which are contained inside the dense, central&#160;core called the nucleus, with electrons present around the ...

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 ...

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 ...

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 ...

Coulomb's Law

Experiments with electric charges have shown that if two objects each have an electric charge, they exert an electric force on each other. The magnitude ...

Electric Charges

From lightning during thunderstorms to electronic devices, the phenomenon of electromagnetism is all around us. The electromagnetic force is one of the ...

sources-and-properties-of-electric-charge

Sources and Properties of Electric Charge

All objects we see around us consist of atoms, which combine to form molecules. The lightest element in the universe is hydrogen, and a hydrogen atom ...

Types of Forces

In most situations, forces can be grouped into two categories: contact forces and field forces.&#160; Contact forces occur as a result of direct physical ...

Electric Fields

Source: Yong P. Chen, PhD, Department of Physics &#38; Astronomy, College of Science, Purdue University, West Lafayette, IN
An electric field is generated ...

Intermolecular Forces

Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions ...

Van der Waals Interactions

Atoms and molecules interact with each other through intermolecular forces. These electrostatic forces arise from attractive or repulsive interactions ...

Chemical Bonds


Atoms participate in a chemical bond formation&#160;to acquire a completed valence-shell electron configuration similar to that of the noble gas nearest ...

Electron Behavior

Electrons are negatively charged subatomic particles attracted to and orbit around the positively-charged nucleus of an atom. They reside in spaces ...

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 ...

Ions and Ionic Charges

In ordinary chemical reactions, the nucleus &mdash; which contains the protons and neutrons of each atom and thus identifies the element &mdash; remains ...

Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level and the composition of the nucleus of atoms.  Clarification Statement: Chemistry: Examples of properties that could be predicted from patterns could include reactivity of metals, types of bonds formed, numbers of bonds formed, atomic radius, atomic mass, or reactions with oxygen. Emphasis is on main group elements and qualitative understanding of the relative trends of ionization energy and electronegativity.

HS-PS1-1

Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3&#8211;12 are ...

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 ...

Chemical Reactions

A chemical reaction is a process by which the bonds in the atoms of substances are rearranged to generate new substances. Matter cannot be created or ...

Chemical Equations

Chemical equations represent the identities and relative quantities of substances involved in a chemical reaction. The substances undergoing reaction are ...

Introduction to Chemical Reactions

All chemical reactions begin with a reactant, the general term for one or more substances entering the reaction. Sodium and chloride ions, for example, ...

Temperature Dependence on Reaction Rate

The Collision Theory
Atoms, molecules, or ions must collide before they can react with each other. Atoms must be close together to form chemical bonds. ...

stoichiometry-product-yield-and-limiting-reactants

Stoichiometry, Product Yield, and Limiting Reactants

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Preparation of 25% v/v Ethylenediamine in Deionized WaterExpand
	Here, we show the laboratory ...

physical-and-chemical-properties-of-matter

Physical and Chemical Properties of Matter

The characteristics that enable us to distinguish one substance from another are called properties.

Physical Properties of Matter

A physical property is ...

Dynamic Equilibrium

A reversible chemical reaction represents a chemical process that proceeds in both forward (left to right) and reverse (right to left) directions. When ...

Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.  Clarification Statement: Chemistry: Examples of chemical reactions could include the reaction of sodium and chlorine, carbon and oxygen, or carbon and hydrogen. Reaction classification aids in the prediction of products (e.g. synthesis, decomposition, single displacement, double displacement, and acid-base).

Intermolecular vs Intramolecular Forces

Intermolecular forces (IMF) are electrostatic attractions arising from charge-charge interactions between molecules. The strength of the intermolecular ...

comparison-between-electrical-and-gravitational-forces

Comparison Between Electrical And Gravitational Forces

There are four fundamental forces in nature: the gravitational force, the electromagnetic force, the strong nuclear force, and the weak nuclear force. To ...

intermolecular-forces-and-physical-properties

Intermolecular Forces and Physical Properties



Intermolecular forces are attractive forces that exist between molecules. They dictate several bulk properties, such as melting points, boiling points, ...

electric-field-of-two-equal-and-opposite-charges

Electric Field of Two Equal and Opposite Charges

Atoms generally contain the same number of positively and negatively charged particles, protons, and electrons. Hence, they are electrically neutral. ...

Electric Field

Consider two point charges, each exerting Coulomb force on the other. It is possible to describe the Coulomb interaction via an intermediate step by ...

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 ...

Electric Dipoles and Dipole Moment

Consider two charges of equal magnitude but opposite signs. If they cannot be separated by an external electric field, the system is called a permanent ...

Plan and conduct an investigation to gather evidence to compare the structure of substances at the macroscale to infer the strength of electrical forces between particles.  Clarification Statement: Emphasis is on understanding the strengths of forces between particles, not on naming specific intermolecular forces (such as dipole-dipole). Examples of particles could include ions, atoms, molecules, and network solids (such as graphite). Examples of macro-properties of substances could include the melting point and boiling point, vapor pressure, and surface tension.

HS-PS1-3

bond-dissociation-energy-and-activation-energy

Bond Dissociation Energy and Activation Energy

Bond energy is the energy required to break a bond homolytically. These values are usually expressed in units of kcal/mol or kJ/mol and are referred to as ...

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, ...

Coupled Reactions

Cellular processes such as building and breaking down complex molecules occur through stepwise chemical reactions. Some of these chemical reactions are ...

energy-diagrams-transition-states-and-intermediates

Energy Diagrams, Transition States, and Intermediates

Free-energy diagrams, or reaction coordinate diagrams, are graphs showing the energy changes that occur during a chemical reaction. The reaction ...

What is Metabolism?

Overview

Metabolism represents all of the chemical activity in a cell, including reactions that build molecules (anabolism) and those that break ...

types-of-chemical-reactions-anabolic-and-catabolic

Types of Chemical Reactions: Anabolic and Catabolic

The first law of thermodynamics holds that energy can neither be created nor destroyed&#8212;it can only change form. An organism&#39;s essential function ...

Non-equilibrium in the Cell

An important concept in studying metabolism and energy is that of chemical equilibrium. Most chemical reactions are reversible. They can proceed in both ...

Activation Energy

Activation energy is the minimum amount of energy necessary for a chemical reaction to move forward. The higher the activation energy, the slower the rate ...

Energy Transfer in Chemical Reactions

Chemical reactions require sufficient energy to cause the matter to collide with enough precision and force that old chemical bonds can be broken and new ...

factors-influencing-the-rate-of-chemical-reactions

Factors Influencing the Rate of Chemical Reactions

A variety of factors influence the rate of chemical reactions. For a chemical reaction to happen, atoms must collide with enough energy to overcome the ...

Predicting Reaction Outcomes

Kinetics describes the rate and path by which a reaction occurs. In contrast, thermodynamics deals with state functions and describes the properties, ...

States of Matter and Phase Changes

The internal energy of a substance&#8212;the total kinetic energy of all its molecules and the potential energy of their associated forces&#8212;depends ...

Develop a model to illustrate that the release or absorption of energy from a chemical reaction system depends upon the changes in total bond energy.  Clarification Statement: Emphasis is on the idea that a chemical reaction is a system that affects the energy change.  Examples of models could include molecular-level drawings and diagrams of reactions, graphs showing the relative energies of reactants and products, and representations showing energy is conserved.

HS-PS1-4

Transition Metals in the Periodic Table

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