An atom with 2 protons and 3 neutrons is called a **deuteron**. It is a type of hydrogen atom, with one proton and one electron. The deuteron is a stable isotope of hydrogen, which means that it does not decay into other elements over time.
The deuteron is heavier than the more common hydrogen isotope, protium, which has only one proton. This is because the deuteron has an extra neutron in its nucleus. The extra neutron gives the deuteron a mass of 2.014102 u, while protium has a mass of 1.007825 u.
The deuteron is used in a variety of applications, including nuclear fusion, nuclear fission, and medical imaging. In nuclear fusion, two deuterons combine to form a helium nucleus, releasing a large amount of energy. In nuclear fission, a heavy nucleus, such as uranium-235, is split into two smaller nuclei, releasing a large amount of energy. In medical imaging, deuterons are used to create images of the body.