Selenium
Express your answer in condensed form, in order of increasing orbital energy. For example,[He]2s^22p^2.
To determine the condensed electron configuration of selenium in order of increasing orbital energy, we follow these steps:
Step 1: Find the atomic number of selenium.
Selenium has an atomic number of 34.
Step 2: Determine the electron configuration of the lowest energy levels (up to the noble gas before selenium).
The noble gas before selenium is argon (atomic number 18), with the electron configuration: 1s^2 2s^2 2p^6 3s^2 3p^6.
Step 3: Distribute the remaining electrons of selenium.
Since selenium has 34 electrons, we fill up the orbitals in the following order:
1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^4.
Step 4: Condense the electron configuration.
To condense the electron configuration, we write the noble gas configuration (argon) in brackets and continue with the remaining electrons outside the brackets.
The condensed electron configuration for selenium is therefore: [Ar] 4s^2 3d^10 4p^4.
Note: This condensed form indicates that the noble gas configuration (argon) remains unchanged, and the valence electrons (in the outermost orbitals) are shown outside the brackets.