Why are noble gases the least reactive nonmetal group?
They have 7 valence electrons.
They have 8 electrons.
They have 7 electrons.
They have 8 valence electrons.
They have 8 valence electrons.
Noble gases, such as helium, neon, argon, krypton, xenon, and radon, are the least reactive nonmetal group because they have a full valence electron shell. Specifically, noble gases possess 8 valence electrons, apart from helium which has only 2. Having a complete valence shell gives them a stable electron configuration, making them very unreactive. This stability arises from the fact that their outermost energy level is completely filled with electrons, which creates a strong electrostatic force that prevents them from easily gaining or losing electrons in chemical reactions. Therefore, noble gases rarely form compounds with other elements, leading to their classification as nonreactive gases.
Noble gases are the least reactive nonmetal group because they have full valence electron shells. The valence electron shell is the outermost energy level of an atom that participates in chemical bonding. For noble gases, their valence electron shells are completely filled with electrons.
To understand why noble gases have full valence electron shells, we need to look at their electron configurations. The electron configuration of an atom describes how the electrons are arranged within its energy levels or shells.
Noble gases have the following electron configurations:
Helium (He): 1s²
Neon (Ne): 1s² 2s² 2p⁶
Argon (Ar): 1s² 2s² 2p⁶ 3s² 3p⁶
Krypton (Kr): 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶
Xenon (Xe): 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶
As you can see, noble gases, except for helium, have eight valence electrons in their outermost shell (except helium which has only two). This is significant because the octet rule states that atoms tend to gain, lose, or share electrons in order to achieve a stable electron configuration with eight electrons in their outermost shell. Since noble gases already have stable, full valence electron shells, they have no tendency to gain, lose, or share electrons, making them highly unreactive.
In summary, noble gases are the least reactive nonmetal group because they have full valence electron shells, consisting of eight electrons (except for helium which has two), and thus do not need to gain, lose, or share electrons to achieve stability.