Question

Selenium has six valence electrons. What is the valence of selenium?

Answer 1

The six electrons in the outermost shell allow selenium to have a variety of valence numbers.

The valence of selenium depends on which compound it is in. Selenium is very similar to sulfur. It may have a valence of 6.
EXAMPLE:

 selenium hexafluoride SeF6, selenium trioxide SeO3 


May have 4;

example

selenium tetrafluoride SeF4, selenium dioxide SeO2

MAy have 2;
 
example

selenium difluoride SeF2, selenium dichloride SeCl2 

and may have -2;

example

hydrogen selenide H2Se