Organização da eletrosfera [Módulo 02 - Aula 05]

Summary

This video lesson continues the study of atoms, focusing on the concept of the electron cloud, or 'eletrosfera.' It covers Bohr's model of electrons orbiting in energy levels and the refinement proposed by Sam Feld in 1915. The video explains the division of energy levels into sublevels (spdf) and how these are quantified, with a discussion on the maximum number of electrons per level. It also touches on the equations for electron distribution and transitions between energy states, clarifying the theoretical vs. practical outcomes. The session concludes with a review exercise and an invitation for further learning.

Takeaways

• 😀 The lesson continues the study of the atom, focusing on the concept of the electrosphere and its energy levels.
• 😀 The Bohr model proposed that electrons orbit around the nucleus in discrete energy levels, based on hydrogen's emission spectrum.
• 😀 Bohr's model is demonstrated using a hydrogen lamp that passes light through a prism, creating light beams that split into various colors.
• 😀 In 1915, a new model was proposed by Sam Feld, which divided Bohr's energy levels into sublevels, such as ellipses.
• 😀 Sam Feld's model further refined the understanding of the atomic structure by explaining the splitting of spectral lines into multiple parts.
• 😀 Energy levels in the atom are divided into 7 distinct levels, each with a maximum number of electrons that can occupy them.
• 😀 The maximum number of electrons in a level is determined by the equation 2m², where 'm' is the level number. However, this equation works well only for the first four levels.
• 😀 For higher levels (5, 6, and 7), the practical electron numbers are smaller than the theoretical values suggested by the equation.
• 😀 The electron configuration includes sublevels spdf, with each sublevel having its own maximum electron capacity (e.g., s = 2, p = 6, d = 10, f = 14).
• 😀 The lecture explains the concept of atomic excitation: an electron can absorb energy and jump to higher levels, then release the same amount of energy when returning to lower levels.
• 😀 In the exercise section, the correct interpretation of the hydrogen atom's behavior is addressed, with an explanation of how different energy levels and wavelengths relate to the emission and absorption of light.

Q & A

What is the basic idea behind Bohr's model of the atom?

Bohr proposed that electrons orbit the nucleus in fixed energy levels, with each level corresponding to a specific amount of energy. This was based on the emission spectra of hydrogen gas, where light passing through a prism formed distinct lines.

How did Sam Feld's model improve upon Bohr's theory?

Sam Feld proposed that the energy levels Bohr described were not just simple orbits, but were subdivided into sublevels. These sublevels, based on the analysis of spectra, offered a more refined explanation of electron behavior in atoms.

How are the energy levels of an atom numbered in the context of Bohr's and Feld's models?

In Bohr’s model, the energy levels are numbered from 1 to 7. Feld's refinement added the concept of sublevels within these levels.

What is the maximum number of electrons that can occupy each energy level?

The maximum number of electrons in each level is calculated using the formula 2n², where n is the energy level number. For example, the first level can hold 2 electrons, the second can hold 8, and so on, with deviations observed in higher levels.

How does the formula 2n² work in determining the number of electrons in an energy level?

The formula 2n² gives the theoretical maximum number of electrons each energy level can hold, where 'n' is the energy level number. For example, for the 1st level (n=1), it holds 2 electrons; for the 2nd level (n=2), it holds 8 electrons, and so on.

What is the discrepancy between the theoretical and actual electron counts in energy levels 5, 6, and 7?

While the formula predicts higher numbers (e.g., 50, 72, 98 for levels 5, 6, and 7), the actual observed numbers are 32, 18, and 8, respectively. These variations are due to practical constraints and limitations in atomic structure.

What are the sublevels in an atom and how are they represented?

The sublevels in an atom are labeled as s, p, d, and f. These sublevels each have a specific maximum number of electrons they can hold: s (2 electrons), p (6 electrons), d (10 electrons), and f (14 electrons).

Why is the formula 2n² accurate up to the 4th energy level but not beyond?

The formula 2n² works accurately for the first four energy levels, but beyond that, practical observations deviate due to more complex electron interactions and orbital limitations in higher energy levels.

What does the term 'excited state' refer to in atomic physics?

An excited state occurs when an electron absorbs energy and jumps to a higher energy level, away from its ground state. This higher energy state is less stable, and the electron may eventually return to the ground state by releasing energy.

What is the relationship between the energy of an electron and its distance from the nucleus?

The farther an electron is from the nucleus, the higher its energy. This is because the attraction between the electron and the nucleus weakens as the electron moves further away, making it easier to remove the electron from the atom.