Question

all elements on the periodic table are reactive, except for group which has valence e.

Explanation:

Step1: Recall noble gases properties

Noble gases (group 18) are inert.

Step2: Determine valence electrons

They have 8 valence electrons (except helium which has 2, but in general context for group 18 as a whole when considering most elements in the group, 8 is the common valence electron number for stability).

Answer:

18, 8