The correct response to describe why the expression is incorrect is:
A neutron should be expressed as \( ^1_0n \), not \( ^0_1n \).
The notation for a neutron is typically written as \( ^1_0n \), where the superscript (1) represents the mass number and the subscript (0) represents the atomic number. In the original expression \( ^0_1n \), these numbers are in the wrong positions. The mass number (total number of protons and neutrons) should be at the top, and the atomic number (which is 0 for neutrons) should be at the bottom.