Konfigurasi Elektron dan Elektron Valensi- Kimia SMA kelas 10 semester 1

Summary

In this educational video, viewers are introduced to electron configuration and valence electrons, concepts crucial for understanding atomic structure. The video explains the arrangement of electrons in atomic shells, following Bohr's atomic theory, and outlines key rules for electron configuration. Through practical examples, the concept of valence electrons—the electrons in the outermost shell—is demonstrated. The presenter explains how to write electron configurations for various elements and highlights the importance of valence electrons in determining chemical properties. The lesson concludes with a promise for further learning in upcoming videos.

Takeaways

• 😀 Electron configuration refers to the arrangement of electrons in the atomic shells of an atom.
• 😀 According to Bohr's atomic model, electrons are arranged in shells or orbits around the atomic nucleus, with each shell having a specific capacity.
• 😀 The first shell (K shell) can hold a maximum of 2 electrons, the second shell (L shell) can hold 8 electrons, the third shell (M shell) can hold 18 electrons, and the fourth shell (N shell) can hold 32 electrons.
• 😀 The formula for determining the maximum number of electrons in each shell is 2n^2, where n is the shell number (K=1, L=2, M=3, etc.).
• 😀 To write the electron configuration, the number of electrons in each shell is listed in order, starting from the first shell.
• 😀 Valence electrons are the electrons located in the outermost shell of an atom and are responsible for an atom's chemical properties.
• 😀 For example, carbon (C) with atomic number 6 has the electron configuration 2.4, and its valence electrons are 4.
• 😀 Sodium (Na) with atomic number 11 has the electron configuration 2.8.1, and its valence electron is 1.
• 😀 To determine valence electrons, simply look at the number of electrons in the outermost shell of the atom.
• 😀 Practice examples included magnesium (Mg, atomic number 12), scandium (Sc, atomic number 21), and arsenic (As, atomic number 33), where their electron configurations and valence electrons were calculated step by step.

Q & A

What is electron configuration?

Electron configuration refers to the arrangement of electrons in the atomic shells of an element. It describes how electrons are distributed among different shells around the nucleus of an atom.

What is the maximum number of electrons that can be in each shell?

The maximum number of electrons that each shell can hold is determined by the formula 2n², where 'n' is the shell number. For example, the first shell can hold a maximum of 2 electrons, the second shell can hold up to 8 electrons, the third shell can hold up to 18 electrons, and the fourth shell can hold up to 32 electrons.

How do you determine the electron configuration for an atom?

To determine the electron configuration, you start by filling the lowest energy shells first, based on the atomic number of the element. You continue filling shells until all the electrons are accounted for, following the maximum electron capacity for each shell.

Can you give an example of how to write an electron configuration for an atom?

For example, for carbon (atomic number 6), the electron configuration is 2.4. The first shell holds 2 electrons, and the second shell holds 4 electrons.

What are valence electrons?

Valence electrons are the electrons located in the outermost shell of an atom. They play a key role in chemical bonding and reactions.

How can you determine the number of valence electrons from an electron configuration?

The number of valence electrons corresponds to the number of electrons in the outermost shell. For example, if the electron configuration is 2.4, the valence electrons would be 4.

What is the electron configuration for sodium (Na)?

Sodium has an atomic number of 11. Its electron configuration is 2.8.1, meaning the first shell has 2 electrons, the second shell has 8 electrons, and the third shell has 1 electron.

What are the valence electrons for magnesium (Mg)?

Magnesium (atomic number 12) has the electron configuration 2.8.2. The valence electrons are 2, as they are in the outermost shell.

How do you write the electron configuration for an atom with an atomic number of 33?

For an element with an atomic number of 33, like arsenic (As), the electron configuration would be 2.8.18.5. This means the first shell has 2 electrons, the second shell has 8, the third shell has 18, and the fourth shell has 5 electrons.

Why is it important to understand electron configuration and valence electrons?

Understanding electron configuration and valence electrons is crucial because they help explain how atoms interact, form bonds, and participate in chemical reactions. The distribution of electrons determines an element's chemical properties and behavior.