Answer:
[Kr] 4d² 5s²
Explanation:
In group 2 and period 2 is the element Zirconium. Here's an example A noble gas configuration of an atom consists of the elemental symbol of the last noble gas prior to that atom, followed by the configuration of the remaining electrons. So for sodium, we make the substitution of [Ne] for the 1s22s22p6 part of the configuration. Sodium's noble gas configuration becomes [Ne]3s1.
