The number of neutrons and electrons, respectively, present in the radioactive isotope of hydrogen is :
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To find the number of neutrons in an isotope, subtract the atomic number (bottom number, Z) from the mass number (top number, A). For a neutral atom, the number of electrons is always equal to the atomic number.
Hydrogen has three main isotopes:
1. Protium ($^1_1$H): 1 proton, 0 neutrons. It is stable.
2. Deuterium ($^2_1$H): 1 proton, 1 neutron. It is stable.
3. Tritium ($^3_1$H): 1 proton, 2 neutrons. It is radioactive.
The question asks about the radioactive isotope of hydrogen, which is Tritium ($^3_1$H).
For any atom or isotope, the superscript is the mass number (A) and the subscript is the atomic number (Z).
Mass Number (A) = (Number of protons) + (Number of neutrons)
Atomic Number (Z) = Number of protons
For Tritium, $A=3$ and $Z=1$.
Number of protons = Z = 1.
Number of neutrons = A - Z = 3 - 1 = 2.
In a neutral atom, the number of electrons is equal to the number of protons.
Number of electrons = Z = 1.
The question asks for the number of neutrons and electrons, respectively.
The values are 2 and 1.
