Distribuição eletrônica [Módulo 02 - Aula 06]

Summary

This video explains the concept of electron configuration, focusing on how electrons are distributed across energy levels and sublevels in atoms according to the Aufbau principle. It covers key topics such as the diagonal rule for filling sublevels, the determination of valence electrons, and the process of creating electron configurations for various elements, including iron (Fe) and chromium (Cr). The video also introduces noble gas notation, simplifying electron configurations by using the closest noble gas as a core reference. The content is designed to help students understand and apply these concepts in chemistry.

Takeaways

• 😀 The video explains how electron distribution in atoms follows a specific model called the Pauli diagram, which organizes electrons in increasing order of energy levels and sublevels.
• 😀 Electrons are distributed in energy levels and sublevels based on the maximum number of electrons each can hold. These numbers vary per level and sublevel, such as 2 for the 1s, 6 for the 2p, and 10 for the 3d.
• 😀 The distribution of electrons begins with the lowest energy level, filling sublevels in a diagonal order, not sequentially by number. This is referred to as the 'order of diagonals.'
• 😀 Each energy level can hold a different number of electrons, with specific sublevels (s, p, d, f) filling up first, based on their capacity.
• 😀 In the case of iron (Fe), the electron distribution starts with the 1s sublevel and continues through the 4s and 3d, with 26 electrons in total for a neutral atom.
• 😀 The 'valence shell' refers to the outermost energy level of an atom, which in the case of iron, is the 4s2 sublevel.
• 😀 The 'highest energy sublevel' is the one that has the most energy in the electron configuration, which, for iron, is 3d6.
• 😀 When dealing with ions like Fe3+, electrons are removed from the outermost shell, starting with the 4s sublevel, then the 3d sublevel.
• 😀 For a 3+ ion of chromium (Cr), the electron configuration would be similar to argon (Ar), but with adjustments made to the 3d and 4s sublevels, following the principle of electron removal from the valence shell.
• 😀 The script introduces the concept of 'core electron configuration' (also called the noble gas shorthand), which simplifies the electron configuration by referencing the electron configuration of the nearest noble gas.
• 😀 The lesson emphasizes understanding how to apply the Pauli diagram for electron distribution, whether for neutral atoms or ions, and how to simplify configurations using noble gases as shorthand.

Q & A

What is the main topic discussed in the video transcript?

The main topic discussed in the video transcript is the electronic configuration of atoms, focusing on how electrons are distributed in energy levels and sublevels, following the model proposed by Pauli.

What is the significance of the Pauli diagram in understanding electron distribution?

The Pauli diagram is significant because it describes the order in which electrons fill the energy levels and sublevels. It helps visualize how electrons are distributed in atoms, following specific rules regarding the maximum number of electrons in each sublevel and energy level.

How many electrons can each energy level (n=1 to n=7) accommodate?

Each energy level can accommodate the following maximum number of electrons: 1st level (2), 2nd level (8), 3rd level (18), 4th level (32), 5th level (32), 6th level (18), and 7th level (8).

What are the maximum number of electrons that can fit into each sublevel (s, p, d, f)?

The maximum number of electrons that can fit into each sublevel are as follows: s (2), p (6), d (10), and f (14).

What is the meaning of the term 'valence shell' or 'valence level'?

The valence shell refers to the outermost energy level of an atom, where the valence electrons reside. These electrons are crucial for chemical bonding. In the example of iron (Fe), the valence shell is 4s².

What does the term 'highest energy sublevel' refer to?

The highest energy sublevel is the sublevel with the highest energy within an atom’s electron configuration. In the case of iron (Fe), this is the 3d⁶ sublevel.

How do you determine the electronic configuration of an ion, such as Fe³⁺?

To determine the electronic configuration of an ion like Fe³⁺, start with the neutral atom’s configuration, and then remove electrons from the valence shell. For Fe³⁺, three electrons are removed: two from the 4s² and one from the 3d⁶ sublevel.

What is meant by the 'diagonal rule' in electron configuration?

The 'diagonal rule' refers to the method of filling the sublevels based on their diagonal positions in the Pauli diagram. This rule ensures the correct order of filling the sublevels from the lowest to the highest energy.

What is the electronic configuration of a neutral chromium (Cr) atom?

The electronic configuration of a neutral chromium (Cr) atom, with 24 electrons, is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁴.

How is the electron configuration of chromium 3+ (Cr³⁺) different from the neutral chromium atom?

In the case of Cr³⁺, three electrons are removed from the neutral chromium atom. Two electrons are removed from the 4s² sublevel and one from the 3d⁴ sublevel, resulting in the configuration 3d³.

Why is the electron configuration of noble gases like Argon often used in shorthand notation?

Noble gases like Argon are used in shorthand notation (core notation) because they have a stable and complete electron configuration. This allows for a more concise representation of the electron configuration of elements, focusing on the electrons outside the noble gas core.