Question

The nucleus of tritium consists of:
A.1 proton + 1 neutron
B. 1 proton + 3 neutrons
C. 1 proton + zero neutrons
D. 1 proton + 2 neutrons

Answer 1

Hint: Elements having same atomic numbers but different atomic masses are termed as isotopes. As atomic masses are the sum of the number of protons and neutrons, so the isotopes contain different numbers of protons and neutrons. Isotopes of hydrogen are protium, deuterium and tritium having atomic mass of 1 u, 2 u and 3 u respectively.

Complete answer:
Isotope is the property of any element to possess the same atomic number with different mass numbers. The mass of an atom is concentrated in the nucleus because atomic mass is the sum of the number of protons and neutrons. The alteration in the number of neutrons gives rise to different atomic masses but same atomic numbers. The number of protons is the atomic number.
Hydrogen has 3 isotopes named as protium, deuterium and tritium. Protium is the form of hydrogen that has 1 atomic number and 1 u atomic mass, that is it has 1 proton and 0 neutron in its nucleus. While deuterium consists of atomic number 1 and atomic mass 2 u due to 1 proton and 1 neutron in the nucleus.
So, tritium has atomic number 1 and atomic mass 3 u, as it has 1 proton and 2 neutrons in its nucleus.
Therefore, the nucleus of tritium consists of 1 proton + 2 neutrons.

So option D is correct.

Note:
The ability to possess isotopes by an element gives rise to the phenomena of radioactivity and nuclear reactions that creates new compounds by the reaction of the nuclides of various isotopes. These reactions can happen as nuclear fission, where a higher isotope breaks and forms simpler atoms, or in form of nuclear fusion, where a simpler isotope fuses with another nuclide to form a new compound.