The monoatomic ion X2 has 25 electrons and 29 neutrons. What is the identity of element X? A. CO B. B C. Mn D. Cu OB D Question 4 1 pts Which correctly lists a noble gas, a metal, a nonmetal, and semimetal (metalloid) in that order? A. Kr, Pd, Se, Ge B. Xe, Si, Al, Sb C. Ar, Ag, N, Br D. Ne, Ni, Li, B OB OD