Neon and sodium exhibit dramatically different reactivities due to their distinct positions in the periodic table and their corresponding electron configurations.
Reactivity of Neon:
- Group: Neon is in Group 18, which contains the noble gases.
- Atomic Number: Neon has an atomic number of 10, which means it has 10 electrons.
- Electron Configuration: The electron configuration of neon is \( 1s^2 2s^2 2p^6 \), meaning it has a full valence shell with 8 electrons in its outer shell (the maximum for the second period). This full outer shell contributes to its stability and lack of reactivity.
- Properties: Noble gases, including neon, are characterized by their inertness because they do not tend to gain, lose, or share electrons; they typically do not form chemical bonds with other elements. As a result, neon is non-reactive under standard conditions.
Reactivity of Sodium:
- Group: Sodium is in Group 1, which contains the alkali metals.
- Atomic Number: Sodium has an atomic number of 11, giving it 11 electrons.
- Electron Configuration: The electron configuration for sodium is \( 1s^2 2s^2 2p^6 3s^1 \). This configuration shows that sodium has one electron in its outermost shell (the 3s orbital), making it highly reactive.
- Properties: Alkali metals are known for their tendency to lose that single outer electron easily to achieve a stable electron configuration resembling that of neon (i.e., attaining a full outer shell of 8 electrons). This makes sodium very reactive, particularly with nonmetals like chlorine and oxygen.
Summary of Differences in Reactivity:
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Full vs. Partial Valence Shell:
- Neon has a full valence shell, leading to its inertness.
- Sodium has one electron in its outer shell, making it prone to losing that electron and thus reactive.
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Group Characteristics:
- Neon, a noble gas, is non-reactive.
- Sodium, an alkali metal, is highly reactive.
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Tendency to Form Compounds:
- Neon does not readily form compounds due to its stable electron configuration.
- Sodium readily forms compounds (like sodium chloride) by donating its outer electron.
In conclusion, the reactivity of neon is negligible compared to that of sodium, primarily due to neon's achieved stability from its full outer electron shell and sodium's eagerness to lose its single outer electron to achieve stability.