Question

An atom of selenium (Se) forms a monatomic ion. Which of the following ions does it most likely form? Se2+ Se2 Se6+ Se6 *Not expecting an answer, but an explanation to how to figure it out?*

Answer 1

I didn't know Selenium was considered organic? :P atoms form ions that mimic the electronic structure of noble gases. so add or subtract electrons from the atom to achieve the configuration of a noble gas.

Answer 2

Se2-

Step-by-step explanation:

Selenium is in group six, it has the configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4. We can see that each selenium atom is missing two electrons to fill its fourth energy level. It is more energetically favorable for it to gain two electrons than lose four electrons. So the likely ion is Se2-