nuclear chemicals such as plutonium
The meaning of the word nuclear weapon, is a weapon that has a nuclear warhead on it.
* Earthquake Richter 5.0 = 32 kilotons nuclear weapon, like was used at Nagasaki * Earthquake Richter 6.0 = 1 megaton nuclear weapon * Earthquake Richter 7.0 = 32 megaton nuclear weapon * Earthquake Richter 7.1 = 50 megaton nuclear weapon, Tsar Bomba, the largest nuclear weapon ever tested * Earthquake Richter 8.0 = 1 gigaton nuclear weapon, much larger than anything ever made
The atomic bomb was the first nuclear weapon ever made during World war two and it was the first weapon that have been tested before Hiroshima was under attack.
The largest KNOWN nuclear weapon was made by the Soviet Union (Russia) and was called the "Tsar Bomba" (King of Bombs). It had a yield of ~50MT.
This nuclear weapon is called an atomic bomb or a nuclear bomb
An atomic weapon is an alternative name for a nuclear weapon, a weapon which derives its energy from the nuclear reactions of either fusion or fission.
Nuclear weapon detonations
If by "bomb" you mean a conventional explosive weapon, then the nuclear weapon is more powerful.
Originally as a defense against Nazi Germany possibly making one.
Uranium 235, or plutonium, depending on weapon design
That would vary from weapon to weapon.