KIMIA UNSUR - MATERI KIMIA KELAS 12 | Edcent.id

Summary

In this educational video, Kak Tiar from adsense.id explores the chemistry of noble gases, focusing on Group 8A elements in the periodic table. The video covers their characteristics, electron configurations, and their unique stability, explaining how these gases, such as helium, neon, argon, krypton, xenon, and radon, possess full valence electron shells. Kak Tiar also discusses their physical and chemical properties, including trends in atomic size, ionization energy, and reactivity. Despite their high stability, some noble gases can still react under certain conditions. The video concludes with practical applications of these gases, such as in lighting, cancer therapy, and balloon filling.

Takeaways

• 😀 Noble gases belong to Group 8A (or Group 18) in the periodic table and are known for their stability.
• 😀 The noble gases include Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn).
• 😀 These elements are stable because they have a full outer electron shell, following the octet rule (8 electrons), except Helium, which follows the duet rule (2 electrons).
• 😀 The electron configurations of noble gases are as follows: He (2), Ne (2,8), Ar (2,8,8), Kr (2,8,18), Xe (2,8,18,18), Rn (2,8,18,32).
• 😀 Noble gases are chemically inert due to their high ionization energies, making them unlikely to form bonds.
• 😀 Helium is unique among noble gases because it only requires 2 electrons to be stable, unlike the others that require 8.
• 😀 The periodic trends for noble gases show that as you move down the group, atomic radius, boiling point, melting point, and density increase.
• 😀 The ionization energy of noble gases decreases as you move down the group due to the increasing distance between the nucleus and valence electrons.
• 😀 Noble gases are generally non-reactive, but under certain conditions (like heating or electrical energy), elements like Xenon and Radon can react with highly reactive elements like Fluorine.
• 😀 Noble gases have various applications: Helium is used in balloons, Neon in neon signs, Argon in light bulbs, Krypton in high-intensity lamps, Xenon in camera flash, and Radon is used in cancer therapy.

Q & A

What are the main groups in the periodic table of elements?

The main groups in the periodic table are Group A (main groups) and Group B. Group A consists of 8 groups, and Group B also consists of 8 groups, making a total of 18 groups.

Why are the elements in Group 8A called noble gases?

The elements in Group 8A, also known as noble gases, are called so because they are very stable and have low reactivity. This stability is due to their complete electron configuration.

What are the elements in Group 8A (noble gases)?

The elements in Group 8A, or noble gases, are Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn).

How are valence electrons determined for elements in Group 8A?

Valence electrons are determined by the electron configuration of the elements. For noble gases, the electron configuration ends with 8 electrons in the outermost shell, which makes them stable, except for Helium, which has 2 valence electrons.

What is the octet rule, and how does it apply to noble gases?

The octet rule states that atoms tend to gain, lose, or share electrons to achieve a stable electron configuration with 8 electrons in the outermost shell. This applies to noble gases, which already have a full outer shell of 8 electrons, making them stable.

Why is Helium an exception to the octet rule?

Helium is an exception because it has only 2 electrons, but it is still stable due to its full 1s orbital. This is why Helium follows the duet rule instead of the octet rule.

What is the trend in atomic radius and ionization energy in Group 8A elements?

In Group 8A, as you move down the group, the atomic radius increases because the number of electron shells increases. Conversely, ionization energy decreases because the outermost electrons are further from the nucleus and are more easily removed.

How does the boiling point and melting point of noble gases change as you go down the group?

As you go down Group 8A, the boiling and melting points increase. This is due to stronger London dispersion forces between the atoms, which become more significant as atomic size and mass increase.

Why do noble gases have relatively low boiling and melting points?

Noble gases have relatively low boiling and melting points because they only experience weak London dispersion forces (a type of van der Waals force) between their non-polar atoms, which require less energy to overcome.

What are some uses of noble gases?

Noble gases have various applications. For example, Helium is used in balloons, Neon is used in neon signs, Argon is used in light bulbs, Krypton is used in high-intensity lamps, Xenon is used in camera flash lamps, and Radon is used in cancer therapy.