The nucleus of tritium consists of _______________.

Tritium is the isotope of hydrogen element.

Tritium has one proton and two neutrons of its nucleus.

$\underset{\left(\text{Protium}\right)}{1^{{\text{H}}^1}}\underset{\left(\text{Deutirium}\right)}{1^{{\text{H}}^2}}\underset{\left(\text{Tritium}\right)}{1^{{\text{H}}^3}}\text{Hydrogen\hspace{0.17em}Isotopes}$

For tritium, $\text{Z}=1\text{\hspace{0.17em}and\hspace{0.17em}A}=3$

So, number of neutrons in tritium is

$\text{Neutrons}=\text{A}-\text{Z}$

                $=3-1=2$