[Ar] 3d10 4s2 4p4
or
2, 8, 18, 6
Selenium does not have a second electron affinity because adding an additional electron to selenium would require more energy to overcome the repulsion between the negatively charged electron and the negatively charged selenium ion. In other words, the energy required to add a second electron to selenium is higher than the energy released in the process.
Selenium has a lower electron affinity than germanium. Electron affinity is the energy released when an atom gains an electron to form a negative ion. In general, electron affinity tends to decrease as you move down a group in the periodic table, which is why selenium has a lower electron affinity than germanium.
The electron configuration of selenium is [Ar]3d10.4s2.4p4.
Selenium has 6 valence electrons
Selenium has 5 filled electron shells. The electron configuration for selenium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4.
The valence electron configuration of selenium is 4s2 4p4, meaning it has 6 valence electrons.
Selenium has 6 electrons in its outermost shell.
Se2- 1s22s22p63s23p64s23d104p6
1s2 2s2 2p63s2 3p6 3d104s2 4p4
Potassium and selenium can form an ionic bond, where potassium will donate an electron to selenium to achieve a stable electron configuration. This results in the formation of potassium selenide (K2Se).
The electron configuration of selenium (Se) is [Ar] 3d10 4s2 4p4. To form a 2- ion, two electrons will be removed from the outermost shell, which is the 4p subshell. Therefore, the electron configuration of Se2- is [Ar] 3d10 4s2.
Selenium typically loses 2 electrons to achieve a stable electron configuration. This results in the formation of a 2+ ion for selenium.