do we subtract the number of electrons from the number of protons to find the number of neutrons in an atom?

1 answer

No, subtracting the number of electrons from the number of protons does not give you the number of neutrons in an atom. The number of neutrons in an atom is found by using the atomic mass and the number of protons.

Here's how it works:

  1. Atomic Number (Z): This is the number of protons in the nucleus of an atom, which also equals the number of electrons in a neutral atom.

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

To find the number of neutrons (N), you can use the following formula:

\[ N = A - Z \]

Where:

  • \( N \) is the number of neutrons,
  • \( A \) is the mass number,
  • \( Z \) is the atomic number (number of protons).

In summary, you need the mass number to find the number of neutrons, not just the number of protons and electrons.