Write the atomic symbols for isotopes with the following characteristics?

1)an oxygen atom with 10 neutrons
2)a neon atom with twelve neutrons
3)25 electrons and 28 neutrons
4)a mass number of 24 and 13 neutrons
5)a titanium atom with 25 neutrons

The isotopes are represented with two numbers before the atom symbol. One number means the atomic number (number of protons) and is placed on the left lower corner, the other number is that mass number (number of protons and neutrons) and is placed on the right upper corner. With that, 1) (8, 18) O: 8 is the atomic number and 18 is the mass number; 2) (10, 22) Ne: 10 is the atomic number and 22 is the mass number; 3) (25, 53) Mn: 25 is the atomic number and 53 is the mas number; 4) (11, 24) Na: 11 is the atomic number and 24 is the mass number; (22, 47) Ti: 22 is the atomic number and 47 is the mass number. The two numbers are placed without parentheses, again atomic number on the left lower corner and the mass number on the left upper corner.

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.

Solubility would be your answer.