2. There are only three isotopes of hydrogen: there are 1 proton in the nucleus of Xi (P) and no neutron, with an abundance of 99.98%; Deuterium (D) (also called heavy hydrogen) has 1 proton and 1 neutron in its nucleus, with an abundance of 0.016%. Tritium (T) (also called superheavy hydrogen) has 1 proton and 2 neutrons in its nucleus, with an abundance of 0.004%.
3. Deuterium and tritium are the main substances involved in nuclear fusion reaction, which are actually used in the preparation of hydrogen bombs. Bili Bili originated from the ability of Shiba Tatsuya, the protagonist in The Inferior Student of the Academy of Wizardry, to directly cast spells on water droplets in the air and decompose them into such elements, thus triggering a nuclear fusion blow. He once destroyed a country's fleet with one blow in this way, leaving the name of Aotian Long, the anti-X-man. Therefore, as soon as the phrase appears, it represents a word-pack to force. Another explanation is that the symbols of deuterium and tritium are both H( 1 1H, 2 1H, 3 1H), which add up to HHH, hahaha, hahaha, hehehe, and so on.
The periodic table of elements is a spoof lyric of Li Li rap and musical ghosts, which is also common in other regions and is used for funny interaction.