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

Summary

In 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.