how many neutrons does neon-12 have?

Neon is an inert element and has an atomic number of 10. The atomic mass of Neon is 20. However, there are a number of isotopes of neon, including, Neon-16, Neon-19, Neon-20, Neon-21, Neon-22, Neon-23, Neon-24, etc. Among these, the three stable isotopes of Neon are Neon-20, Neon-21, and Neon-22.
Remember that the isotopes of an element have the same atomic number but different atomic masses.
The atomic mass of an atom is equal to the sum of the protons and neutrons. The atomic number of an atom is equal the number of protons it contains. Hence, Neon has 10 protons.
Neon-20 has 10 neutrons since its atomic mass is 20 (10 protons + 10 neutrons). Similarly, a Neon-21 atom has 10 protons and 11 neutrons. And, a Neon-22 atom has 10 protons and 12 neutrons.
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