Name: halogens: trends and reactions
Uploaded: 2020-09-03T13:38:28.000Z
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Halogens

Галогены это группа из пяти неметаллических элементов фтора, хлора, брома, йода и астата принадлежащих к 17-й группе. Элементарные галогены существуют в виде двухатомных молекул. При комнатной температуре фтор и хлор являются газами, бром жидкостью, а йод твердым веществом.Меньше известно о свойствах пятого элемента, астата, который является редким и высокорадиоактивным твердым веществом. Физические свойства галогенов, такие как цвет элемента, меняются при движении вниз по группе. Атомные радиусы увеличиваются с увеличением атомного номера, а температура плавления и кипения показывает тенденцию к увеличению от фтора к йоду.Напротив, периодические свойства, такие как электроотрицательность, реакционная способность и сродство к электрону, снижаются в группе. Электронные конфигурации галогенов указывают на то, что они имеют семь валентных электронов и одного электрона не хватает до ближайших конфигураций благородного газа. Таким образом, галогены обладают высокой электроотрицательностью с сильной тенденцией к получению одного дополнительного электрона для завершения своего октета, что делает их высокоактивными и мощными окислителями по сравнению с другими группами.Фтор самый сильный окислитель среди галогенов, а йод самый слабый. Галогены также проявляют резко отрицательное сродство к электрону, которое представляет собой изменение энергии, когда электрон захватывается нейтральным атомом. Оно выражается в килоджоулях на моль, а отрицательное значение указывает на экзотермический характер реакции.Галогены реагируют с большинством металлов с образованием галогенидов металлов. Например, хлор и натрий реагируют с образованием хлорида натрия, который является ионным соединением. Галогены реагируют с водородом с образованием полярных ковалентных соединений, называемых галогенидами водорода, которые часто растворяются в воде с образованием галогеноводородных кислот.Галогены также реагируют с водой. Реакция фтора с водой сильно экзотермична, с образованием фтороводорода сильной кислоты и кислорода. Однако хлор реагирует медленнее, образуя соляную кислоту и хлорноватистую кислоту сильные окислители.Кроме того, галогены могут реагировать друг с другом с образованием бинарных ковалентных соединений, называемые межгалогенными соединениями. Например, бром реагирует с фтором, образуя трифторид брома.

Галогены

Элементы группы 17, известные как галогены, не являются металлами. При комнатной температуре фтор и хлор являются газами, бром — жидкостью, а йод — твёрдым. Астатин является крайне нестабильным радиоактивным элементом, поэтому в настоящее время большая часть его свойств неизвестна из-за короткого полураспада. Теннессин также является синтетическим элементом, который, по прогнозам, будет находиться в этой группе.  
 
 Галогены встречаются не в виде отдельных атомов, а в виде двухатомных молекул. Атомный радиус увеличивается от фтора к йоду. Электронная конфигурация валентной оболочки галогенов составляет ns2np 5 , и они имеют тенденцию принимать электрон для получения конфигурации с благородным газом. & nbsp; Различные свойства галогенов перечислены в таблице 1. 
 
 Таблица 1: Свойства галогена. 
 
 <table style=""margin-left: auto; margin-right: auto;"">
 <tbody style=""border: 1px solid black;"">
 <tr>
 <td style=""color: black; border: 1px solid black; text-align: center;"">Элемент </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">Электронная конфигурация </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">Радиус атома (pm) </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">IE1 (кДж/моль) </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">EA (кДж/моль) </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">Плотность при 25 °C. </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">Температура плавления (°C) </td>
 </tr>
 <tr>
 <td style=""color: black; border: 1px solid black; text-align: center;"">F </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">[HE] 2s22p5 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">71 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">1680 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">-328 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">1.70 г/л. </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">-219 </td>
 </tr>
 <tr>
 <td style=""color: black; border: 1px solid black; text-align: center;"">CL </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">[NE] 3s23p5 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">99 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">1250 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">-348 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">3.12 г/л. </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">-101 </td>
 </tr>
 <tr>
 <td style=""color: black; border: 1px solid black; text-align: center;"">Br </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">[AR] 4s24p5 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">114 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">1140 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">-324 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">3.19 г/см3 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">-7 </td>
 </tr>
 <tr>
 <td style=""color: black; border: 1px solid black; text-align: center;"">I </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">[Сr] 5s25p5 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">133 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">1010 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">-295 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">3.96 г/см3 </td>
 <td style=""color: black; border: 1px solid black; text-align: center;"">114 </td>
 </tr>
 </tbody>
 </table>
 
 Сродство к электронам у галогенов имеют большие отрицательные значения; таким образом, галогенами являются мощные окислители. Фтор является самым мощным окислителем группы с самым отрицательным сродством электронов. Галогены реагируют с металлами с получением электрона, и производят соответствующий галогенид металла. Например, хлор вступает в реакцию с железом, чтобы дать ему хлорид железа и натрий, чтобы дать хлорид натрия. Галогеновые микроорганизмы реагируют с водородом на образование галогенидов водорода, которые растворяются в воде для получения гидрогалогенных кислот. Гидрофтористовая кислота является самой слабой галокислотой. Фтор активно реагирует с водой. Реакция очень экзотермическая и вырабатывает кислород. Реакция хлора менее энергичная с водой. При этой реакции образуется гипохлородная кислота, которая является сильным окислителем. 
 
 < Галогены реагируют друг с другом с образованием межгалогенных соединений, многие из которых являются бинарными соединениями. Общая молекулярная формула межгалогенных соединений - AB n , где A - галоген с более высоким атомным номером и нечетное число. Немногочисленными примерами межгалогенных соединений являются ICl, IBr, BrF, BrCl, ClF. Галогены реагируют с углеродом с образованием коммерчески важных соединений. & nbsp; Например, этилен реагирует с фтором с образованием перфторэтилена. 
 
 Этот текст адаптирован из <a href="https://openstax.org/books/chemistry-2e/pages/6-5-periodic-variations-in-element-properties">Openstax, Химия 2е изд., раздел 6.5: Периодические изменения свойств элемента.</a>

Элементы группы 17, известные как галогены, являются неметаллами. При комнатной температуре фтор и хлор являются газами, бром – жидкостью, а йод – твердым веществом. ...

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halogens: trends and reactions

Halogens are Group 17 nonmetals that show clear trends in structure and reactivity. At room temperature, fluorine and chlorine are gases, bromine is a liquid, and iodine is a solid. Astatine is highly unstable and radioactive, so most of its properties are still unknown because it has a very short half-life. Tennessine is a synthetic element that is also predicted to belong to this group.

These elements do not usually exist as single atoms. Instead, they form diatomic molecules, which means each molecule has two atoms. Their atomic radius increases from fluorine to iodine, and their outer-shell electron pattern is ns2 np5. This electron arrangement helps explain why halogens tend to gain one electron and reach a noble gas configuration.

The table of halogen properties shows important changes across the group. Fluorine has the smallest atomic radius, while iodine has the largest. First ionization energy decreases from fluorine to iodine, and electron affinity stays strongly negative for the group. Because of this, halogens are powerful oxidizing agents, and fluorine is the strongest oxidizing agent in the group.

Halogens react with metals to form metal halides. For example, chlorine reacts with iron to make iron chloride, and it reacts with sodium to make sodium chloride. They also react with hydrogen to form hydrogen halides. When these dissolve in water, they produce hydrohalic acids, and hydrofluoric acid is the weakest haloacid.

Halogens also react with water, but not in the same way. Fluorine reacts very vigorously, and the reaction is highly exothermic, which means it releases a large amount of heat. It also produces oxygen. Chlorine reacts less vigorously with water, and the hypochlorous acid formed is a strong oxidizing agent.

Halogens can react with one another to form interhalogen compounds, which are often binary compounds. Their general formula is ABn, where A is the halogen with the higher atomic number and n is an odd number. Examples include ICl, IBr, BrF, BrCl, and ClF. Halogens also react with carbon to form useful compounds, such as perfluoroethylene from the reaction of ethylene with fluorine.

Halogens: Trends and Reactions

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halogens

Halogens are Group 17 nonmetals that show clear trends in structure and reactivity. At room temperature, fluorine and chlorine are gases, bromine is a liquid, and iodine is a solid. Astatine is highly unstable and radioactive, so most of its properties are still unknown because it has a very short half-life. Tennessine is a synthetic element that is also predicted to belong to this group. These elements do not usually exist as single atoms. Instead, they form diatomic molecules, which means...

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Explore halogen trends, from physical states and electron configuration to oxidizing strength, metal halides, hydrohalic acids, and interhalogen compounds.

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The Periodic Table

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Ionic Radii

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Ionization Energy

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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 ...

Alkali Metals

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Group 17 elements, known as halogens, are nonmetals. At room temperature, fluorine and chlorine are gases, bromine is a liquid, and iodine a solid. ...

Noble Gases


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Use the Periodic Table as a model to predict the relative properties (metallic/nonmetallic character, ionic charge, and reactivity) and arrangement of elements based on the pattern of valence electrons in the outermost energy levels of atoms.

Types of Chemical Bonds

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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 ...

Covalent Bonding and Lewis Structures

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Bonding in Metals

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Construct an explanation to classify the type of chemical bond that occurs (covalent, ionic, or metallic) in a given substance.

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Nomenclature of Alkanes

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Understand types, properties, and structure of matter.

Halogens: Trends and Reactions

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