Number of Neutrons in heavy hydrogen atom are ___________?

The correct answer is 1.

CONCEPT:

• Isotopes: Isotopes are atoms of the same element that have different numbers of neutrons(mass number) but the same number of protons and electrons(atomic number).
• Deuterium(heavy Hydrogen) and Tritium are isotopes of hydrogen.
   

EXPLANATION:

• Heavy hydrogen(Deuterium) is ₁D² or ₁H².
• Number of neutrons = Mass number(A) - Atomic number(Z)
• For heavy hydrogen, Mass number = 2 and Atomic number = 1.
• Number of neutrons = 1.

Thus, Heavy hydrogen contains one proton and one neutron.