Answer:
Period 6 Group 1A
Step-by-step explanation:
All the elements are arranged in the periodic table , according to their atomic number ,
The element given in the question is Cesium ( Cs ) , the number of valence electrons , i.e. , the number of electrons in the last shell of the atom , is equal to 1 .
hence , it corresponds to the group 1A , and the period 6 .