Algodoo

No they dont't fuse or collide but this is how atoms work. But they are not to scale. Protium has less pull on it's electron so it's electron has a higher degree of freedom. Approved by my Chemistry Teacher BTW. XD. Protium, Deuterium, Tritium. I only did the 3 most common btw.

Protium is the most stable and common isotope of hydrogen comprising about 99.98% of hydrogen on earth.

Deuterium is far more rare representing 0.0026% of our planet's hydrogen, but is mostly stable, and non-radioactive.

Tritium is heavy hydrogen, it is radioactive, with a half-life of 12.32 years, it can created by ccosmic rays interacting with the atmosphere or through nuclear fusion, both in very small amounts. Likewise It can also be used in Thermonuclear weapons to increase potency. But because It is rather difficult to create safely, it is dangerous, it decays over short periods of time, and isn't always stable.