Answer:
s orbital
Explanation:
The elements of Group 1 (IA) and Group 2 (IIA) have one and two electrons in their outermost shells respectively.
For the elements in group Group 1 (IA), the general outer electron configuration is ns1. This last electron is accommodated within an s orbital.
For the elements in Group 2 (IIA), the two outermost electrons are accommodated in an ns orbital, hence the answer.
