Argon has 3 naturally occurring isotopes , ar 36, ar 38, and ar 40. what is the mass # of each and how many protons, neutrons, and electrons are present in each?

Ar 36:  Mass number 36,  18 Protons,  18 neutrons and 18 electrons.

Ar 38:  Mass number 38,  18 Protons,  20 neutrons and 18 electrons.

Ar 40:  Mass number 40,  18 Protons,  22 neutrons and 18 electrons.

Explanation:

The number given after 'Ar'  is the mass number.

The atomic number of Argon is 18 which means that 18 protons and 18 electrons are in the atom of Argon. The mass number of an isotope = number of protons + the number of neutrons.