1). Enrico Fermi directed construction of the the thing that achieved the first sustained nuclear chain reaction, under the stadium at the University of Chicago.
3). 'Fission' means splitting one big thing up into several smaller things.
4). The atomic mass of an atom is close to the sum of all the neutrons and protons in its nucleus.
5). 'Fusion' means several small things joining to form a bigger thing.
6). Henri Becquerel is credited with discovering radioactivity.
7). The names of Madame Marie and Mssr. Pierre Curie were appropriated after their deaths and used as the unit of radiation.
2). I have no idea what that symbol means, but 'neutron' is the only choice left.
