Models or kinds? I will assume kinds:
no
all nuclear explosives use some fission. even now.
Some atomic bombs explode on impact, most explode in the air for maximum destruction caused by the explosion spreading out over a wider area.
fission and in some fusion
the sun, atomic bombs, nuclear power plants
They made some 5-15 small Hydrogen Bombs.
Many different types of ammunition were used by various countries during World War II. Some were bombs dropped from airplanes, bullets shot from different types of guns, and torpedoes shot from submarines.
bullets missles rockets bombs
Japan has never had atomic weapons. There were two atomic weapons used against Japan by the US in August 1945. Please do some reading.
not alot for some reason
Atomic bombs, A bombs, fission bombsHydrogen bombs, H bombs, fusion bombsBoosted fission bombs, "dial-a-yield" bombsMultistaged fusion bombsClean fusion bombs, reduced fallout fusion bombsSalted fusion bombs, dirty fusion bombs, increased fallout fusion bombsetc.
so if some other country nukes us we can nuke them and us having the biggest bombs is intimadating to other countries with nukes