what is the number of protons, neutrons, and electrons of 2H and how do you calculate it?

²H

(Find the atomic number using the Periodic Table. The superscript at the top-left-corner of the symbol is the mass number.)
(Number of protons = No. of electrons = Atomic number)
(Number of neutrons = [Mass number] - [Atomic number])

The atomic number of H is 1. The mass of number of ²H is 2.
Number of protons = No. of electrons = 1
Number of neutrons = 2 - 1 = 1

'2H' ??? Do you mean hydrogen with atomic mass of 2'.
If so
Protons = 1
Neutrons = 1
Electrons = 1

In the periodic table elements are shown as [2/1] - H .
The '2' indicates the atomic mass.
The '1' indicates the atomic number.

The atomic mass is the sum of all the protons and neutrons in the nucleus.
The atomic number is the number of protons in the nucleus.
So subtracting 2 - 1 = 1 is the number of neutrons in the nucleus.

Hydrogen has three isotopes. viz. Protium ,Deuterium, & Tritium
Their nuclear arrangements are
protium ; 1 proton, 0 neutrons & 1 electron
deuterium ; 1 proton , 1 neutron, & 1 electron
tritium ; 1 proton , 2 neutrons, & 1 electron.
The next element in the periodic table is helium
[2/2] - He ; 2 protons, 2 neutrons, & 2 electrons.

NB
Protium is normal abundant hydrogen
Deutrerium is 'Heavy hydrogen'. often given the symbol 'D'.
Tritium is 'Super heavy hydrogen'. and is radio-active.

Hope that helps!!!!