You can't solve for the number of neutrons directly. However, you can calculate it using the following information:

1. Atomic Number (Z): This represents the number of protons in an atom's nucleus.

2. Mass Number (A): This represents the total number of protons and neutrons in an atom's nucleus.

Formula:

* Number of neutrons (N) = Mass Number (A) - Atomic Number (Z)

Example:

* Carbon has an atomic number of 6 (meaning it has 6 protons) and a mass number of 12.

* Therefore, Carbon has 12 - 6 = 6 neutrons.

Important Notes:

* Isotopes: Atoms of the same element can have different numbers of neutrons. These variations are called isotopes. For example, Carbon-12 and Carbon-14 are both isotopes of Carbon. Carbon-12 has 6 neutrons, while Carbon-14 has 8 neutrons.

* Periodic Table: The periodic table can be used to determine the atomic number of an element.

* Mass Spectrometer: A mass spectrometer can be used to determine the mass number of an element.

Let me know if you have any specific element in mind, and I can help you calculate the number of neutrons!