how to find number of electrons

To find the number of electrons in an atom or ion, follow these steps:

1. Identify the atomic number (also called the proton number) of the element from the periodic table. This number equals the number of protons in the atom.
2. For a neutral atom (no charge), the number of electrons is equal to the atomic number since the positive charge of protons balances the negative charge of electrons.
3. For ions:
   • If the ion is positively charged (cation), subtract the charge from the atomic number to get the number of electrons.
   • If the ion is negatively charged (anion), add the charge to the atomic number to find the number of electrons.

Example: For Mg2+ ion with atomic number 12,
Number of electrons = 12 - 2 = 10 electrons. This method works because electrons and protons balance each other’s charge in neutral atoms, and charges affect the electron count in ions accordingly.