For that you have to use the Aufbau principle
For example, writing the electronic configuration of Fe(28)
I recommend that you memorize the aufbau principle. Once you learn it, you don’t need anything else except the atomic number of the element to write it’s electronic configuration.
Answer:- The charge is +2.
Explanations:- Z stands for atomic number. The Z is given as 25 means the atomic number of the element is 25. It has 23 electrons. For a neutral atom the number of electrons is same as the atomic number. Since the number of electrons is less than atomic number, the atom must have lost the electrons.
Number of electrons lost = 25 - 23 = 2
If the element lost electrons then it has positive charge. As, the electrons are lost, the charge is +2.
The answer would be "Gas".
