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
