Question

An element has 18 electrons in the outer most shell. The element is
(A) Transition metal
(B) Rare earth metal
(C) Alkaline earth metal
(D) Alkali metal​

Answer 1

Answer:

You might even claim that krypton has 18 electrons in its shell, but that's terribly misleading. It has 8 electrons in its outermost shell, and 18 electrons in its next-inner shell. Ditto again in the fifth period, where the 5s orbitals fill, then 4d.