what happens to the half-life and mass of reactants broken down during a nuclear decay reaction?

the half-life of the reactants in a nuclear decay reaction remains constant over time, and the mass of the reactants that are consumed stays the same.
the half-life of reactants in a nuclear decay reaction remains constant over time, but the mass of reactants that are consumed decreases.
the half-life of reactants in a nuclear decay reaction decreases over time, but the mass of the reactants that are consumed stays the same.
the half-life of reactants in a nuclear decay reaction increases over time, and the mass of the reactants that are consumed increases.

The half-life of reactants in a nuclear decay reaction remains constant over time, but the mass of reactants that are consumed decreases.

Explanation:

The half-life is defined as the time in which half of the starting number of radioactive atoms decayed in products. The half-life it is a intrinsec property of the reactant atom and it is a constant. As time passes more and more atoms are decaying through the nuclear reaction so the quantity of the radioactive compounds (reactant) is decreasing.

the electronic configuration of an atom with eight electrons is 1s²2s²2p⁴. the orbital diagrams are shown in the figure.

as per the hunds rule:

1. electrons tend to avoid being in the same orbital as per as practicable.

2. electrons in different orbitals of the same energy will have their spin parallel.

this can be illustrated from the multiplicity of the orbitals of the atom. as there are four electrons in the p orbital and p orbital has 3 sub-shells. the electrons can be fed in different ways as shown in the figure but the correct orbital diagram will be as per the hunds rule.