List three other elements that have 8 valence electrons Hint Refer to the periodic table.
The Correct Answer and Explanation is :
Elements with eight valence electrons are found in Group 18 of the periodic table, commonly known as the noble gases. The three primary noble gases besides the well-known element neon (Ne) are argon (Ar), krypton (Kr), and xenon (Xe). Each of these elements has a full outer electron shell, which contributes to their chemical stability and nonreactivity.
- Argon (Ar): Argon is the third noble gas and is located in period 3 of the periodic table. It has an atomic number of 18, which means it has 18 electrons. The electron configuration of argon is [Ne]3s²3p⁶, indicating that its outermost shell contains 8 electrons. Because of its complete valence shell, argon is chemically inert and does not readily form compounds under standard conditions. Argon is commonly used in lighting (such as in fluorescent lamps) and as an inert gas in various industrial applications.
- Krypton (Kr): Krypton, with an atomic number of 36, is found in period 4 of the noble gases. Its electron configuration is [Ar]3d¹⁰4s²4p⁶, which also indicates that krypton has 8 valence electrons in its outermost shell. Krypton is used in high-performance lighting, photography, and certain types of lasers. Its stability makes it a suitable choice for applications where reactivity must be minimized.
- Xenon (Xe): Xenon is located in period 5 and has an atomic number of 54. Its electron configuration is [Kr]4d¹⁰5s²5p⁶, demonstrating that it also possesses a full outer shell of 8 electrons. Like argon and krypton, xenon is known for its inertness. It finds applications in high-intensity discharge lamps, ion propulsion systems, and certain types of medical imaging.
In summary, argon, krypton, and xenon each have 8 valence electrons due to their complete outer shells, which is a defining characteristic of noble gases that contributes to their lack of reactivity and stability in chemical interactions.