I don’t understand your question. Did you need to know more about the valency or the electrons of valance. In either case the answer is the similar.
See,
The atomic code of Mercury is ( 80Hg
) therefore its electronic configuration
1s22s22p63s23p64s23d104p65s24d105p66s24f145d10
The final electron is inserted into the sub-shell 5d. However, the outermost shell is the 6th and the 6th shell contains only a sub-shell of 6s. The 6s sub-shell is home to two electrons. Thus, Mercury has two valence electrons. Because Mercury is able to donate these two electrons of the 6s it also has valency 2.
So, the Valency/Valence electrons of Mercury are 2.