Answer:
D. A²⁺
Explanation:
Element from Group 2A -
The element of group 2A are known as the alkaline earth metals ,
The elements of this group are - beryllium (Be) , magnesium (Mg) , calcium (Ca) , strontium (Sr) , barium (Ba) , and radium (Ra).
The valence shell of these elements have two valence electrons and therefore , if the element need to stabilizes itself , it need to lose these two electrons and attain noble gas configuration,
Therefore ,
After losing the two electrons , the element becomes A²⁺.
Hence , the ions are symbolized as A²⁺.