Electron Configuration - Basic introduction

Summary

This video provides a clear introduction to writing electron configurations for elements. It starts by explaining the atomic structure of nitrogen and how to assign electrons to sublevels like 1s, 2s, and 2p. The video moves on to demonstrate the electron configurations for aluminum and iron (Fe2+), showing how to adjust for ions by adding or removing electrons. It emphasizes the importance of understanding energy levels and sublevels (s, p, d, f) and offers tips for transition metals. The video concludes with an example for chlorine and its chloride ion.

Takeaways

• 🧪 Nitrogen's atomic number is 7, so its electron configuration focuses on 7 electrons.
• 🔢 The first energy level contains only the 1s sublevel, which can hold 2 electrons.
• 💡 The second energy level includes both the 2s and 2p sublevels, where s holds 2 and p holds 6 electrons.
• 🧬 For nitrogen, the electron configuration is 1s² 2s² 2p³, totaling 7 electrons.
• 🔍 For aluminum, which has 13 electrons, the configuration is written up to 13, resulting in 1s² 2s² 2p⁶ 3s² 3p¹.
• 🔋 Transition metals like iron require writing the electron configuration of the neutral atom first before adjusting for ions.
• ➖ The Fe²⁺ ion has 24 electrons, as 2 electrons are lost from the neutral Fe atom with 26 electrons.
• ⚛️ For Fe²⁺, the electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶ after removing two 4s electrons.
• 🧫 For non-transition metal ions like chloride (Cl⁻), you can directly write the electron configuration based on the total number of electrons.
• 🧪 Chlorine's neutral atom has 17 electrons (1s² 2s² 2p⁶ 3s² 3p⁵), while the chloride ion (Cl⁻) has 18 electrons, resulting in a configuration of 1s² 2s² 2p⁶ 3s² 3p⁶.

Q & A

What is the electron configuration of a nitrogen atom?

The electron configuration of a nitrogen atom is 1s2 2s2 2p3, which adds up to 7 electrons.

How do you write the electron configuration for an element?

To write the electron configuration for an element, start from the lowest energy level (1s) and fill up sublevels (s, p, d, f) according to their electron capacity until the total number of electrons equals the atomic number of the element.

Why do we focus on the number of electrons when writing electron configurations?

We focus on the number of electrons because electron configuration represents the arrangement of electrons around the nucleus. The number of electrons equals the atomic number for neutral atoms, while ions may have different numbers of electrons.

How do sublevels (s, p, d, f) differ in terms of electron capacity?

The s sublevel can hold 2 electrons, the p sublevel can hold 6 electrons, the d sublevel can hold 10 electrons, and the f sublevel can hold 14 electrons.

What is the electron configuration of an aluminum atom?

The electron configuration of an aluminum atom (which has 13 electrons) is 1s2 2s2 2p6 3s2 3p1.

How do you adjust the electron configuration for an ion, such as Fe2+?

For an ion like Fe2+, start by writing the electron configuration for the neutral atom (Fe: 1s2 2s2 2p6 3s2 3p6 3d6 4s2). Then, remove electrons based on the charge, starting with the highest energy level. For Fe2+, remove two electrons from the 4s sublevel, resulting in 1s2 2s2 2p6 3s2 3p6 3d6.

Why is it important to remove electrons from the highest energy level when dealing with transition metal ions?

It is important to remove electrons from the highest energy level because electrons in higher energy levels are farther from the nucleus and less tightly bound, making them easier to remove when forming positive ions.

What is the electron configuration of the chloride ion (Cl-)?

The electron configuration of the chloride ion (Cl-) is 1s2 2s2 2p6 3s2 3p6, which accounts for its 18 electrons (17 from chlorine plus one extra electron due to the negative charge).

How does the electron configuration of a negatively charged ion differ from its neutral atom?

For negatively charged ions, you add electrons equal to the charge. For example, the chloride ion (Cl-) has one more electron than a neutral chlorine atom, resulting in an electron configuration of 3p6 instead of 3p5.

When is it necessary to write the electron configuration of the parent atom before adjusting for ions?

It is necessary to write the electron configuration of the parent atom first when dealing with transition metals. This ensures accuracy when removing electrons to account for the positive charge of the ion.