Answer:
The element with electronic configuartion 1s² and atomic number 3 must be an cation.
Explanation:
The "Z" shows the atomic number. Z stand for zahl. It Is German word and meaning is " number".
In given question Z is equal to three which means an element with atomic number three.
Let consider the X is an element with atomic number three having electronic configuration 1s², but according to this atomic number there should be one more electron present is 2s. If X has the electronic configuration 1s² it means that it lose one electron and X is present in the form of cation.
X⁺ = 1s²