Question

in which orbitals would the valence electrons for selenium (se) be placed?
○ s orbital and f orbital
○ s orbital only
○ s orbital and p orbital
○ d orbital only

Explanation:

To determine the orbitals of selenium's (Se) valence electrons, first find its electron configuration. Selenium has an atomic number of 34, so its electron configuration is $1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^4$. Valence electrons are in the outermost shell (n = 4 here). The outermost shell has $4s^2$ (s orbital) and $4p^4$ (p orbital). So valence electrons are in s and p orbitals.

Answer:

s orbital and p orbital