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

Los halógenos son un grupo de cinco elementos no metálicos:flúor, cloro, bromo, yodo y astato, que pertenecen al grupo 17. Los halógenos elementales existen como moléculas diatómicas. A temperatura ambiente, el flúor y el cloro son gases, el bromo es un líquido y el yodo es un sólido.Se sabe menos sobre las propiedades del quinto elemento, el astato, que es un sólido raro y altamente radiactivo. Las propiedades físicas de los halógenos, como el color elemental, varían en función del grupo. Los radios atómicos aumentan al aumentar el número atómico, y el punto de fusión y el punto de ebullición muestran una tendencia ascendente del flúor al yodo.En contraste, las propiedades periódicas como electronegatividad, reactividad y afinidad electrónica disminuyen con en forma descendente por el grupo. Las configuraciones electrónicas de los halógenos indican que tienen siete electrones de valencia y están a un electrón menos de alcanzar sus configuraciones de gas noble más cercanas. Por lo tanto, los halógenos exhiben altas electronegatividades con una fuerte tendencia a ganar un electrón adicional para completar su octeto, lo que los convierte en poderosos agentes oxidantes altamente reactivos en comparación con otros grupos.El flúor es el agente oxidante más potente entre los halógenos y el yodo el menos oxidante. Los halógenos también exhiben afinidades electrónicas altamente negativas, que es el cambio de energía cuando un átomo neutro adquiere un electrón. Se expresa en kilojulios por mol y el valor negativo indica la naturaleza exotérmica de la reacción.Los halógenos reaccionan con la mayoría de los metales para producir haluros metálicos. Por ejemplo, el cloro y el sodio reaccionan para producir cloruro de sodio, que es un compuesto iónico. Los halógenos reaccionan con el hidrógeno para formar compuestos covalentes polares llamados haluros de hidrógeno, que a menudo se disuelven en agua para formar ácidos hidrohálicos.Los halógenos también reaccionan con el agua. La reacción del flúor con el agua es muy exotérmica y produce fluoruro de hidrógeno, un ácido fuerte, y oxígeno. El cloro, sin embargo, reacciona más lentamente, produciendo ácido clorhídrico y ácido hipocloroso, un agente oxidante fuerte.Además, los halógenos pueden reaccionar entre sí, produciendo compuestos covalentes binarios llamados compuestos interhalogenados. Por ejemplo, el bromo reacciona con el flúor formando trifluoruro de bromo.

halógenos

Los elementos del grupo 17, conocidos como halógenos, son no metales. A temperatura ambiente, el flúor y el cloro son gases, el bromo es un líquido y el yodo es un sólido. La astatina es un elemento radiactivo altamente inestable, por lo que actualmente, la mayoría de sus propiedades son desconocidas debido a su corta vida media. El teneso es un elemento sintético que también se predijo que está en este grupo. 
 
 Los halógenos no se encuentran como átomos únicos, sino que existen como moléculas diatómicas. El radio atómico aumenta de flúor a yodo. La configuración electrónica de la capa de valencia de los halógenos es ns2np5, y tienen una tendencia a aceptar un electrón para lograr la configuración de gases nobles.  Las diversas propiedades de los halógenos se enumeran en el cuadro 1.
 
 Tabla 1: Propiedades de los halógenos.
 
 <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;">Elemento</td>
 <td style="color: black; border: 1px solid black; text-align: center;">Configuración electrónica</td>
 <td style="color: black; border: 1px solid black; text-align: center;">Radio atómico (pm)</td>
 <td style="color: black; border: 1px solid black; text-align: center;">EI1 (kJ/mol)</td>
 <td style="color: black; border: 1px solid black; text-align: center;">AE (kJ/mol)</td>
 <td style="color: black; border: 1px solid black; text-align: center;">Densidad a 25 °C.</td>
 <td style="color: black; border: 1px solid black; text-align: center;">Punto de fusión (°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 g/l</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 g/l</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 g/cm3</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;">[Kr] 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;">3,96g/cm3</td>
 <td style="color: black; border: 1px solid black; text-align: center;">114</td>
 </tr>
 </tbody>
 </table>
 
 Las afinidades electrónicas de los halógenos tienen grandes valores negativos; por lo tanto, los halógenos son potentes agentes oxidantes. El flúor es el agente oxidante más poderoso del grupo con la afinidad electrónica más negativa. Los halógenos reaccionan con los metales para ganar el electrón y producir el correspondiente haluro metálico. Por ejemplo, el cloro reacciona con el hierro para formar cloruro de hierro y con el sodio para formar cloruro de sodio. Los halógenos reaccionan con hidrógeno para formar haluros de hidrógeno, que se disuelven en agua para producir ácidos hidrácidos. El ácido fluorhídrico es el hidrácido más débil. El flúor reacciona vigorosamente con el agua. La reacción es altamente exotérmica y produce oxígeno. La reacción del cloro es menos vigorosa con el agua. El ácido hipocloroso producido en esta reacción es un agente oxidante potente.
 
 Los halógenos reaccionan entre sí para formar compuestos interhalógenos, muchos de los cuales son compuestos binarios. La fórmula molecular general para compuestos interhalógenos es ABn, donde A es el halógeno con mayor número atómico y es un número impar. Algunos ejemplos de compuestos interhalógenos son ICl, IBr, BrF, BrCl, ClF. Los halógenos reaccionan con el carbono para formar compuestos de importancia comercial.  Por ejemplo, el etileno reacciona con el flúor para dar perfluoroetileno.
 
 Este texto es adaptado de <a href="https://openstax.org/books/chemistry-2e/pages/6-5-periodic-variations-in-element-properties">Openstax, Química 2e, Sección 6.5: Variaciones Periódicas en las Propiedades de los Elementos.</a>

Halógenos

Los elementos del grupo 17, conocidos como halógenos, son no metales. A temperatura ambiente, el flúor y el cloro son gases, el bromo es un líquido y el yodo un sólido. ...

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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

periodic classification of the elements

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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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Ionic Bonding and Electron Transfer

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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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Understand types, properties, and structure of matter.

Halogens: Trends and Reactions

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