Several thousand, mostly by the US and USSR.
No, Alfred Nobel did not invent atom bombs. He is known for inventing dynamite and establishing the Nobel Prizes. The development of atomic bombs involved the contributions of many scientists, notably led by physicists such as Albert Einstein and J. Robert Oppenheimer.
The key elements to making fission bombs are: Uranium and Plutonium. The specific isotopes of interest are: Uranium-233, Uranium-235, and Plutonium-239. But many other elements are needed to make a functional bomb. As a very rough guess, about a quarter of the elements on the periodic table are needed somewhere in the bomb, roughly 23 different elements in total.
The hydrogen bomb was built because it is more powerful then the atomic bomb. The atomic bomb was the type used on Japan and as bad as those were, hydrogen bombs are even more powerful. Nuclear weapons are very controversial. Most countries want them but they don't want anyone else to have them. The US claims the reason they developed such powerful weapons is a deterrent. The idea is no one will dare attack you if you have such weapons. The atomic bombs used on Japan were very controversial even in the US. Some congress men didn't think it was right to use them on civilians. The reason they did was President Truman and others thought it was the lesser of two evils. They believed the Japanese would fight on for a long time which would kill many more people in the long run then the bombs would. No one knows if that would have been true or not but the bombs did end the war very fast. Japan had little choice but to surrender immediately. Now days that there are several countries with nuclear weapons we have what is called MAD (Mutually Assured Destruction). Both sides are afraid of war because both sides would be destroyed no one would really win. This was the state between the USSR and the US. It may actually have prevented war all these years, because everyone is afraid of the consequences. Hopefully no crazy dictator will get his hands on one and deiced to use it.
There are currently 118 known elements on the periodic table, with elements ranging from hydrogen (atomic number 1) to oganesson (atomic number 118). These elements are organized based on their atomic number and properties, and each element has its own unique characteristics.
There is only one atomic number for any element. For boron, it is 5.
More than a thousand in total. Only one was tested during WW2.
No nuclear bombs were tested on Easter Island.
Because the atomic bombs killed many more Japanese civilians than it did military personel.
Atomic bombs have only been used in combat twice. The US dropped two bombs, one on Nagasaki, one on Hiroshima.
In all nations, several thousand- the exact number is not pulic information. 982 were tested at the Nevada Test Site alone.
their must not been any for the past ten years/twenty years
2
7 :)
By the end of Operation Crossroads in the summer of 1946, the US had built a total of 9 atomic bombs and detonated 5 of them, leaving only 4 in the stockpile. Records obtained by the Bulletin of the Atomic Scientists suggest that by the end of 1946 the US had built 5 more atomic bombs, ending the year with 9 in the stockpile.While the Hanford reactors had a design capacity of 3 atomic bomb cores every month, its very obvious that they were being operated far below capacity through 1945 and 1946 to minimize neutron irradiation damage to the graphite moderator and/or shutdown for repairs frequently.
As both atomic bombs and supernovas vary in yield, this question has no single answer.
Atomic bombs- Zero.
The Manhattan Project began in 1942 and ended in August 1947, with the establishment of the Atomic Energy Commission. A rough estimate is that in this time 15 to 20 atomic bombs had been built, with 5 of those detonated, leaving a stockpile by the time the Manhattan Project ended of 10 to 15 atomic bombs.