Iwill award ! members of the alkaline earth elements have several things in common. they are a) nonmetals and are nonreactive. b) metals with two valence electrons. c) metals that are not very reactive. d) metalloids with two valence electrons. after the fission of u-235 takes place, how many neutrons does the missing nucleus have? a) 84 b) 85 c) 141 d) 143

First question:
All metals 
All share metallic properties
All solids at room temperature

Second question:
In nuclear fission, heavier nuclei breaks into two or more particles which are relatively stable than the former one.
The reaction can be written as,
U-235 > X-k + Kr-92 + 2n
X is the unknown element which is to be determined.
Mass is conserved in Nuclear fission but not in nuclear fusion.

Therefore, mass of X will be 141. Which is an isotope of Barium. Thus the missing element was Barium.
Therefore, X-k = Ba-141, k=141.
Tomic number of Ba is 56. Therefore, number of neutrons of missing nucleus(Barium) = 141 -56 = 85.