Question

Assertion: Binding energy (or mass defect) of hydrogen nucleus is zero.
Reason: Hydrogen nucleus contains only one nucleon.

Answer 1

The hydrogen atom has atomic number one and mass number also equal to one which means the hydrogen has one proton and one electron. The hydrogen atom is electrically neutral as the proton is positively charged and the electron is negatively charged.

Complete step by step solution:
The given problem is an assertion and reason problem. Here we need to find whether the assertion and the reason is correct or wrong and whether the reason supports the assertion or not. The binding energy is energy between two or more particles which is gained by the particles by losing some mass of the particles. The assertion says that the binding energy (or mass defect) of hydrogen nucleus is zero and the reason for this is given as hydrogen nucleus contain only one nucleon, here we see that the hydrogen atom has only proton in the nucleus and no neutron and there is electron only electron in the orbit, in order to have binding energy there should be at least two particles but there is only proton in the nucleus of hydrogen and therefore the binding energy of hydrogen is equal to zero. The assertion and reason both the correct and reason supports the assertion.

Note: In the periodic table has the first element as hydrogen. The atomic number of hydrogen is one and mass number is one. The mass number is equal to the sum of proton and neutron and the atomic number is equal to the number of protons or number of electrons. A Hydrogen atom has one proton and one electron and therefore the hydrogen is electrically neutral.