¿Alguna vez te has preguntado por qué algunos elementos reaccionan... Show more
Química
Inglés
Matemáticas
Lengua Castellana y Literatura
Tips de estudio
FilosofíaSign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
268
•
Updated Mar 16, 2026
•
Tendencias y Propiedades en la Tabla Periódica
1 / 7
Introducción a las Propiedades Periódicas
Las propiedades periódicas son las características de los elementos que varían de forma predecible en la tabla periódica. Esta periodicidad se debe a cómo se repiten las configuraciones electrónicas de la capa de valencia.
Hay dos conceptos clave que explican todo: la carga nuclear efectiva es la carga positiva "real" que siente un electrón de valencia. No es igual al número atómico porque los electrones internos "apantallan" parte de esa carga.
En un periodo (→): Z_ef aumenta porque hay más protones pero los electrones van a la misma capa. En un grupo (↓): Z_ef se mantiene casi constante para la última capa porque aunque hay más protones, también hay más capas internas que apantallan.
¡Dato clave! El efecto pantalla es como un escudo: los electrones internos protegen a los de valencia de la atracción total del núcleo.
Radio Atómico
El radio atómico es la mitad de la distancia entre núcleos de dos átomos idénticos enlazados. Es como medir el "tamaño" de un átomo.
En un grupo (↓): aumenta porque se añaden nuevas capas electrónicas. Cada capa nueva está más lejos del núcleo, así que el átomo es más grande. En un periodo (→): disminuye porque aunque el número de capas es el mismo, la Z_ef aumenta y "tira" más fuerte de los electrones, contrayendo el átomo.
Piénsalo así: es como si el núcleo fuera un imán que se hace más fuerte hacia la derecha (mismo periodo) pero más débil hacia abajo (mismo grupo) debido a la distancia.
Truco para recordar: Los átomos más grandes están en la esquina inferior izquierda, los más pequeños en la superior derecha.
Radio Iónico
Cuando un átomo gana o pierde electrones, su tamaño cambia drásticamente. Los cationes (iones positivos) son más pequeños que el átomo neutro porque al perder electrones, a menudo se pierde toda la capa de valencia y los restantes son atraídos con más fuerza.
Los aniones (iones negativos) son más grandes que el átomo neutro. Al ganar electrones en la misma capa, aumenta la repulsión entre ellos y la nube electrónica se expande.
Para especies isoelectrónicas (mismo número de electrones), a más protones en el núcleo, menor radio. Es lógico: más "tirón" hacia el centro.
Regla fácil: Perder electrones = encogerse, ganar electrones = hincharse.
Energía de Ionización
La energía de ionización (EI) es la energía necesaria para "arrancar" un electrón de un átomo gaseoso. Es como la fuerza que necesitas para separar algo que está pegado.
En un grupo (↓): disminuye porque los electrones están más lejos y más apantallados. En un periodo (→): aumenta porque la Z_ef aumenta y los electrones están más "pegados" al núcleo.
¡Cuidado con las excepciones! Grupo 2 vs. 13: El grupo 13 tiene EI menor porque es más fácil quitar un electrón p que uno de un orbital s completo. Grupo 15 vs. 16: El grupo 16 tiene EI menor porque elimina la repulsión de electrones emparejados.
Para examen: Aprende las excepciones de memoria. Be > B y N > O son preguntas típicas.
Afinidad Electrónica y Electronegatividad
La afinidad electrónica (AE) mide cuánto "le gusta" a un átomo aceptar un electrón. Si es muy negativa, significa que libera mucha energía al aceptarlo (es favorable).
En un grupo (↓): menos negativa (menos favorable) porque el electrón entrante está más lejos del núcleo. En un periodo (→): más negativa (más favorable) porque la Z_ef aumenta.
La electronegatividad es la capacidad de atraer electrones en un enlace. El flúor es el más electronegativo (4.0 en la escala de Pauling). Sigue las mismas tendencias: aumenta hacia la derecha y hacia arriba.
Dato importante: Los gases nobles tienen AE positiva - ¡no quieren electrones extra!
Ejemplos y Casos Prácticos
Para ordenar por radio atómico creciente: P, Cl, Na, Al (todos del periodo 3), aplicamos que el radio disminuye hacia la derecha. Resultado: Cl < P < Al < Na.
Para comparar energías de ionización entre Mg y Al, aunque Al está más a la derecha, EI(Mg) > EI(Al) por la excepción del grupo 2 vs. 13. El electrón 3p del Al es más fácil de arrancar que el 3s del Mg.
Las especies isoelectrónicas como O²⁻, F⁻, Ne, Na⁺, Mg²⁺ se ordenan por número de protones: a más protones, menor radio.
Clave del éxito: En el examen, siempre justifica con Z_ef y apantallamiento, no solo digas "aumenta hacia la derecha".
Resumen para Repasar
| Propiedad | Periodo (→) | Grupo (↓) | Razón |
|---|---|---|---|
| **Radio atómico** | Disminuye | Aumenta | Z_ef vs. capas nuevas |
| **Energía ionización** | Aumenta* | Disminuye | Z_ef vs. distancia+pantalla |
| **Afinidad electrónica** | Más negativa | Menos negativa | Z_ef vs. distancia+pantalla |
| **Electronegatividad** | Aumenta | Disminuye | Z_ef vs. distancia+pantalla |
*Con excepciones importantes
Lo esencial para el examen: definiciones, tendencias generales, justificaciones con Z_ef, excepciones de EI (G2 vs G13, G15 vs G16), y comparación de radios iónicos.
Consejo final: Practica con ejemplos hasta que puedas predecir propiedades sin mirar la tabla. ¡Es como tener superpoderes químicos!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Most popular content in Química
Most popular content
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5
App Store
4.7/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Tendencias y Propiedades en la Tabla Periódica
¿Alguna vez te has preguntado por qué algunos elementos reaccionan violentamente y otros apenas lo hacen? La respuesta está en las propiedades periódicas, esas características que cambian de manera predecible a lo largo de la tabla periódica. Dominar estas tendencias... Show more
Introducción a las Propiedades Periódicas
Las propiedades periódicas son las características de los elementos que varían de forma predecible en la tabla periódica. Esta periodicidad se debe a cómo se repiten las configuraciones electrónicas de la capa de valencia.
Hay dos conceptos clave que explican todo: la carga nuclear efectiva es la carga positiva "real" que siente un electrón de valencia. No es igual al número atómico porque los electrones internos "apantallan" parte de esa carga.
En un periodo (→): Z_ef aumenta porque hay más protones pero los electrones van a la misma capa. En un grupo (↓): Z_ef se mantiene casi constante para la última capa porque aunque hay más protones, también hay más capas internas que apantallan.
¡Dato clave! El efecto pantalla es como un escudo: los electrones internos protegen a los de valencia de la atracción total del núcleo.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Radio Atómico
El radio atómico es la mitad de la distancia entre núcleos de dos átomos idénticos enlazados. Es como medir el "tamaño" de un átomo.
En un grupo (↓): aumenta porque se añaden nuevas capas electrónicas. Cada capa nueva está más lejos del núcleo, así que el átomo es más grande. En un periodo (→): disminuye porque aunque el número de capas es el mismo, la Z_ef aumenta y "tira" más fuerte de los electrones, contrayendo el átomo.
Piénsalo así: es como si el núcleo fuera un imán que se hace más fuerte hacia la derecha (mismo periodo) pero más débil hacia abajo (mismo grupo) debido a la distancia.
Truco para recordar: Los átomos más grandes están en la esquina inferior izquierda, los más pequeños en la superior derecha.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Radio Iónico
Cuando un átomo gana o pierde electrones, su tamaño cambia drásticamente. Los cationes (iones positivos) son más pequeños que el átomo neutro porque al perder electrones, a menudo se pierde toda la capa de valencia y los restantes son atraídos con más fuerza.
Los aniones (iones negativos) son más grandes que el átomo neutro. Al ganar electrones en la misma capa, aumenta la repulsión entre ellos y la nube electrónica se expande.
Para especies isoelectrónicas (mismo número de electrones), a más protones en el núcleo, menor radio. Es lógico: más "tirón" hacia el centro.
Regla fácil: Perder electrones = encogerse, ganar electrones = hincharse.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Energía de Ionización
La energía de ionización (EI) es la energía necesaria para "arrancar" un electrón de un átomo gaseoso. Es como la fuerza que necesitas para separar algo que está pegado.
En un grupo (↓): disminuye porque los electrones están más lejos y más apantallados. En un periodo (→): aumenta porque la Z_ef aumenta y los electrones están más "pegados" al núcleo.
¡Cuidado con las excepciones! Grupo 2 vs. 13: El grupo 13 tiene EI menor porque es más fácil quitar un electrón p que uno de un orbital s completo. Grupo 15 vs. 16: El grupo 16 tiene EI menor porque elimina la repulsión de electrones emparejados.
Para examen: Aprende las excepciones de memoria. Be > B y N > O son preguntas típicas.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Afinidad Electrónica y Electronegatividad
La afinidad electrónica (AE) mide cuánto "le gusta" a un átomo aceptar un electrón. Si es muy negativa, significa que libera mucha energía al aceptarlo (es favorable).
En un grupo (↓): menos negativa (menos favorable) porque el electrón entrante está más lejos del núcleo. En un periodo (→): más negativa (más favorable) porque la Z_ef aumenta.
La electronegatividad es la capacidad de atraer electrones en un enlace. El flúor es el más electronegativo (4.0 en la escala de Pauling). Sigue las mismas tendencias: aumenta hacia la derecha y hacia arriba.
Dato importante: Los gases nobles tienen AE positiva - ¡no quieren electrones extra!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Ejemplos y Casos Prácticos
Para ordenar por radio atómico creciente: P, Cl, Na, Al (todos del periodo 3), aplicamos que el radio disminuye hacia la derecha. Resultado: Cl < P < Al < Na.
Para comparar energías de ionización entre Mg y Al, aunque Al está más a la derecha, EI(Mg) > EI(Al) por la excepción del grupo 2 vs. 13. El electrón 3p del Al es más fácil de arrancar que el 3s del Mg.
Las especies isoelectrónicas como O²⁻, F⁻, Ne, Na⁺, Mg²⁺ se ordenan por número de protones: a más protones, menor radio.
Clave del éxito: En el examen, siempre justifica con Z_ef y apantallamiento, no solo digas "aumenta hacia la derecha".
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Resumen para Repasar
| Propiedad | Periodo (→) | Grupo (↓) | Razón |
|---|---|---|---|
| **Radio atómico** | Disminuye | Aumenta | Z_ef vs. capas nuevas |
| **Energía ionización** | Aumenta* | Disminuye | Z_ef vs. distancia+pantalla |
| **Afinidad electrónica** | Más negativa | Menos negativa | Z_ef vs. distancia+pantalla |
| **Electronegatividad** | Aumenta | Disminuye | Z_ef vs. distancia+pantalla |
*Con excepciones importantes
Lo esencial para el examen: definiciones, tendencias generales, justificaciones con Z_ef, excepciones de EI (G2 vs G13, G15 vs G16), y comparación de radios iónicos.
Consejo final: Practica con ejemplos hasta que puedas predecir propiedades sin mirar la tabla. ¡Es como tener superpoderes químicos!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
2
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Mock Exam
Quiz
Flashcards
Essay
Most popular content in Química
Most popular content
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5
App Store
4.7/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user