What is the electron configuration of Kr?

The electron configuration of krypton (Kr) is [Ar] 3d¹⁰ 4s² 4p⁶.

Krypton is a noble gas located in group 18 of the periodic table. Its atomic number is 36, which means it has 36 electrons. The electron configuration describes how these electrons are distributed among the various atomic orbitals. It follows the Aufbau principle, meaning that electrons fill the lowest energy orbitals first.

The configuration can be broken down as follows:

• [Ar]: This represents the electron configuration of argon, the preceding noble gas, which accounts for the first 18 electrons.
• 3d¹⁰: The next 10 electrons fill the 3d subshell.
• 4s²: The following 2 electrons fill the 4s subshell.
• 4p⁶: Finally, the last 6 electrons fill the 4p subshell, completing the electron configuration.

This configuration indicates that krypton has a stable electron arrangement, which is characteristic of noble gases, making it largely unreactive in chemical interactions.