Modelos atómicos (Goldstein, Becquerel, Curie, Rutherford) - Química Desde Cero

La Química de Yamil

13 Mar 201805:32

Summary

TLDRIn this 'Chemistry from Zero' video, Yamil Córdoba Morena takes viewers on a chronological journey through significant atomic models. Starting with J.J. Thomson's 'plum pudding' model, which posited a uniformly distributed positive charge with electrons embedded within, the video moves on to the discovery of the atomic nucleus by Ernest Rutherford. Rutherford's gold foil experiment revealed a dense, positively charged core, contradicting Thomson's model. The video also touches on the discovery of subatomic particles like electrons, protons, and neutrons, and the phenomenon of radioactivity. The script concludes by highlighting the unsolved mystery of why electrons don't collapse into the nucleus, despite classical physics predicting they would lose energy through radiation.

Takeaways

🌟 The video is an educational series called 'Chemistry from Zero' by Yamil Córdoba Moreno.
🔬 J.J. Thomson proposed a model where the positive part of the atom is uniformly distributed throughout its volume, with electrons embedded in this positive 'plum pudding' matrix.
🌐 Jane Goldstein modified the cathode ray tube design, leading to the discovery of positive rays, later named protons.
🚫 The discovery of protons contradicted the indivisible atom theory proposed by Democritus and Dalton, establishing the existence of subatomic particles with negative and positive charges.
💥 Henri Becquerel and the Curies contributed to the discovery of radioactivity, revealing that atoms can emit different types of radiation: alpha (positive charge), beta (negative charge), and gamma (no charge).
🧬 The understanding evolved to recognize atoms as composed of protons, neutrons, and electrons, with neutrons being neutral particles that do not deflect in electric fields.
💣 Ernest Rutherford conducted gold foil experiments with alpha particles, which led to the discovery that atoms have a dense central nucleus where most of the mass is concentrated.
🚀 Rutherford's model suggested that the nucleus is positively charged, as it repelled positively charged alpha particles, and that electrons orbit around the nucleus.
🔮 Classical physics predicted that electrons orbiting the nucleus would lose energy through electromagnetic radiation, leading to a collapse, which was a problem for the stability of atoms.
🎥 The video concludes with an invitation for viewers to subscribe, share, and like if they enjoyed the content, signaling the end of the educational segment.

Q & A

Who is Yamil Córdoba Morena and what is the purpose of the 'Química desde Cero' video?
-Yamil Córdoba Morena is the presenter of the 'Química desde Cero' (Chemistry from Zero) video series. The purpose of the video is to teach about atomic models, providing a chronological review of the most significant advances in the understanding of the atom and its structure.
What was J.J. Thomson's atomic model like according to the script?
-J.J. Thomson proposed a model where the positive part of the atom was uniformly distributed throughout the volume of the atom, with electrons immersed in this positive matrix like raisins in a pudding.
What modifications did Jane Goldstein make to the cathode ray tube design?
-Jane Goldstein modified the cathode ray tube by perforating the cathode and filling the tube with different gases instead of a vacuum. She observed a new type of glow behind the cathode coming from the anode, which led to the discovery of positively charged rays, later named protons.
How did the discovery of protons challenge the idea of the indivisibility of the atom?
-The discovery of protons, along with the earlier discovery of electrons, confirmed that atoms were not indivisible as previously thought by Democritus and Dalton. Instead, atoms are composed of subatomic particles with electrons carrying a negative charge and protons carrying a positive charge.
What is radioactivity and how was it discovered?
-Radioactivity is a property of some atomic nuclei that emit radiation. It was discovered with contributions from Henri Becquerel and the Curies, among others, who found that certain elements' atoms emit alpha (positively charged), beta (negatively charged), and gamma (no charge) radiation.
What is the significance of Ernest Rutherford's gold foil experiment?
-Ernest Rutherford's gold foil experiment was significant because it led to the discovery that atoms have a dense central nucleus where most of the atomic mass is concentrated. The experiment showed that alpha particles passed through the foil mostly undisturbed, but some were deflected at large angles, suggesting the presence of a small, dense, positively charged nucleus.
According to Rutherford's model, what is the role of electrons in an atom?
-In Rutherford's model, electrons are in constant motion around the nucleus, occupying the majority of the atom's volume, which is mostly empty space.
What problem did classical physics pose for the stability of Rutherford's atomic model?
-Classical physics predicted that an electron, being accelerated as it orbits the nucleus, would continuously emit electromagnetic radiation, losing energy and eventually collapsing into the nucleus, which contradicted the stability of atoms.
What was the final conclusion of the video about the atomic model?
-The final conclusion of the video was that the atomic model had evolved to include a positively charged nucleus and negatively charged electrons in constant motion around the nucleus, but the classical physics issue of electron energy loss and atomic collapse remained unresolved.
What call-to-action did the presenter make at the end of the video?
-The presenter, Yamil Córdoba Morena, encouraged viewers to subscribe to the channel, share the video, and like it if they enjoyed the content.

Outlines

00:00

🔬 Atomic Models and Discoveries

This paragraph introduces the historical development of atomic models. It begins with J.J. Thomson's 'plum pudding' model, which proposed that the positive charge of an atom was uniformly distributed with electrons embedded within it. It then discusses Jane Goldstein's modifications to the cathode ray tube experiment, leading to the discovery of protons as positively charged particles. The paragraph also covers the realization that atoms are not indivisible, as previously thought, but are composed of subatomic particles such as electrons and protons. It mentions Henri Becquerel's contributions and the discovery of radioactivity, which led to the identification of alpha, beta, and gamma radiation. The paragraph concludes with the introduction of neutrons and the atomic structure consisting of protons, neutrons, and electrons.

05:14

🚀 Rutherford's Gold Foil Experiment and Atomic Nucleus

This paragraph delves into Ernest Rutherford's groundbreaking gold foil experiment, which challenged the existing atomic model. Rutherford used alpha particles from a radioactive source to bombard thin gold foil. He observed that most alpha particles passed through with little or no deflection, but some were significantly deflected or even bounced back. This unexpected result led Rutherford to propose a new atomic model with a dense, positively charged nucleus at the center, where most of the atomic mass is concentrated. He also suggested that electrons orbit the nucleus, leaving most of the atom's volume as empty space. However, this model raised a paradox with classical physics, which states that an accelerating electron would emit electromagnetic radiation, causing it to lose energy and spiral into the nucleus, leading to atomic collapse.

📢 Closing Remarks and Call to Action

The final paragraph serves as a closing remark for the video, encouraging viewers to subscribe, share, and like the content. It ends with a casual farewell, signaling the end of the educational video on atomic models and discoveries.

Mindmap

Keywords

💡Modelos atómicos

Atomic models are theoretical representations of the structure of an atom. In the video, the evolution of atomic models is discussed, highlighting significant advancements from early theories to modern understandings, including Thomson's and Rutherford's models.

💡Thomson

J.J. Thomson proposed the 'plum pudding' model of the atom, where electrons are embedded within a positively charged 'pudding.' This model is a key point in the video as it represents an early attempt to describe atomic structure before the discovery of the nucleus.

💡Electrones

Electrons are subatomic particles with a negative charge. The video discusses their discovery and their role in various atomic models, including Thomson's and Rutherford's, emphasizing their importance in the structure of the atom.

💡Protones

Protons are positively charged subatomic particles found in the nucleus of an atom. The video explains their discovery and how they contributed to the disproof of the indivisible atom theory proposed by Democritus, Leucippus, and Dalton.

💡Neutrones

Neutrons are subatomic particles with no electric charge, found in the nucleus of an atom. The video mentions their identification through observations of radiation, which helped refine the understanding of atomic structure.

💡Rutherford

Ernest Rutherford proposed a new atomic model based on his gold foil experiment, which showed that atoms have a small, dense, positively charged nucleus. This model replaced Thomson's and is central to the video's discussion of atomic theory advancements.

💡Radiactividad

Radioactivity is the emission of particles from the nuclei of unstable atoms. The video touches on the contributions of Henri Becquerel and the Curie couple in discovering this property, which furthered the understanding of atomic structure and the existence of subatomic particles.

💡Núcleo atómico

The atomic nucleus is the small, dense region at the center of an atom, containing protons and neutrons. Rutherford's experiments demonstrated the existence of the nucleus, which is a pivotal concept in the video's exploration of atomic models.

💡Partículas alfa

Alpha particles are positively charged particles emitted during radioactive decay. Rutherford used these particles in his gold foil experiment to deduce the presence of a dense nucleus in the atom, as explained in the video.

💡Becquerel

Henri Becquerel discovered radioactivity, observing that certain materials emitted radiation without an external source of energy. The video credits his work as foundational in the development of atomic theory, influencing the understanding of atomic structure.

Highlights

Yamil Córdoba Morena introduces 'Química desde Cero', a chemistry educational series.

The video provides a chronological review of significant advances in atomic models and structure.

J.J. Thomson proposed the 'plum pudding' model of the atom with a uniformly distributed positive charge and electrons embedded within.

Jane Goldstein modified the cathode ray tube experiment, leading to the discovery of protons as positively charged rays.

The discovery of protons contradicted the indivisible atom theory proposed by Democritus and Dalton.

Henri Becquerel and the Curies contributed to the understanding of radioactivity, revealing atoms can emit radiation.

Radioactive emissions include alpha particles (positive charge), beta particles (negative charge), and gamma rays (no charge).

The existence of neutrons was deduced from gamma rays, which are neutral particles not deflected by electric fields.

Atoms are composed of protons, neutrons, and electrons, contradicting earlier models.

Ernest Rutherford conducted the gold foil experiment with alpha particles, leading to a new atomic model.

Rutherford observed most alpha particles passed through the gold foil with little or no deflection.

A few alpha particles were significantly deflected or even bounced back, indicating a concentrated positive charge.

Rutherford proposed the nuclear model of the atom with a dense, positively charged nucleus and electrons orbiting around it.

The classical physics problem of electrons losing energy while orbiting was a challenge for the new atomic model.

The video concludes with an invitation to subscribe, share, and like for more educational content.