3.6.3 - Como fazer a distribuição eletrônica dos elétrons de um átomo: hidrogênio, hélio e lítio

Summary

This video explains how to determine the electronic configuration of simple atoms like hydrogen, helium, and lithium. It starts by introducing the periodic table and walks through the process of assigning electrons to atomic orbitals based on their energy levels and sublevels. The presenter covers key principles such as Pauli's Exclusion Principle, the distribution of electrons in orbitals, and the importance of the number of electrons in determining the configuration. With examples, it demonstrates how to assign electrons to the lowest energy orbitals and how the configuration for elements with more electrons is developed.

Takeaways

• 😀 The script discusses the electronic configuration of simple atoms, specifically hydrogen, helium, and lithium.
• 😀 The key elements in this context are hydrogen (with 1 electron), helium (with 2 electrons), and lithium (with 3 electrons).
• 😀 To configure electrons, the script explains that you must consider three things: energy levels, sublevels, and the number of orbitals corresponding to each sublevel.
• 😀 The first energy level (1) is the least energetic and holds the 1s sublevel, which is spherical in shape and can accommodate a maximum of 2 electrons.
• 😀 Hydrogen, with its single electron, fills the 1s orbital, and its electronic configuration is written as 1s¹.
• 😀 For helium, with two electrons, both electrons fill the 1s orbital, and its configuration is written as 1s².
• 😀 The script explains the Pauli Exclusion Principle, emphasizing that electrons must have opposite spins when they occupy the same orbital.
• 😀 Lithium has three electrons, so after filling the 1s orbital with 2 electrons, the third electron moves to the next energy level in the 2s orbital.
• 😀 Lithium’s full electronic configuration is written as 1s² 2s¹, with the 2s orbital containing one electron.
• 😀 The lesson emphasizes that the first energy level only has the s sublevel, but higher levels can have both s and p sublevels. Therefore, when elements like lithium have more than 2 electrons, they need to occupy higher-energy orbitals.

Q & A

What is the significance of the periodic table in determining the electronic configuration of atoms?

The periodic table helps in determining the number of electrons in an atom, which is crucial for assigning the correct electronic configuration. Each element is associated with a specific atomic number, which corresponds to the number of electrons in the neutral atom.

What is the first orbital that is filled with electrons in an atom?

The first orbital to be filled is the 1s orbital, which is the closest to the nucleus and has the lowest energy level.

How many orbitals are there in the 1s sublevel?

The 1s sublevel has only one orbital, as the 's' orbitals are spherical in shape and can hold a maximum of two electrons with opposite spins.

How is the electronic configuration of hydrogen represented?

The electronic configuration of hydrogen, which has only one electron, is represented as 1s¹. The '1' refers to the first energy level, 's' indicates the type of orbital, and '¹' indicates the number of electrons in that orbital.

What principle governs the distribution of electrons in orbitals?

The Aufbau principle governs the distribution of electrons, stating that electrons fill orbitals starting from the lowest energy level to the highest.

What is Pauli's exclusion principle, and how does it apply to electron configuration?

Pauli's exclusion principle states that no two electrons in an atom can have the same set of quantum numbers. In practice, this means that electrons in the same orbital must have opposite spins.

How many electrons can the 1s orbital hold?

The 1s orbital can hold a maximum of two electrons with opposite spins.

What happens when there are more electrons than can be accommodated in the 1s orbital?

When more electrons are present than can be accommodated in the 1s orbital, the electrons are placed in the next available orbital, starting with the 2s orbital. The electron configuration moves to higher energy levels and sublevels as needed.

How is the electronic configuration of helium different from that of hydrogen?

Helium has two electrons, both of which fill the 1s orbital, resulting in the electronic configuration 1s², while hydrogen has only one electron, giving it the configuration 1s¹.

Why does lithium require an additional orbital compared to hydrogen and helium?

Lithium has three electrons. After filling the 1s orbital with two electrons, the third electron must go into the next available orbital, the 2s orbital, since no p orbitals are available in the first energy level. This results in the electronic configuration 1s² 2s¹.