Which numbers are shown in the symbol for a radioactive nuclide?
the atomic number and the number of neutrons
the mass number and the number of neutrons
the atomic number and the mass number
the number of electrons and the number of protons

The numbers shown in the symbol for a radioactive nuclide ARE THE ATOMIC NUMBER AND THE MASS NUMBER.

Atomic nuclide usually have two number written at their fronts, one is usually written at the top and the second one at the bottom of the nuclide symbol. The number that is written above is the mass number while the one below is the atomic number. Mass number represents the summation of proton and neutron in the nuclide while the atomic number is the number of proton in the atom. For a neutral atom, the number of proton and electron is always the same. For example for alpha particle, which is an helium atom, the figure 4 written in front of its symbol is the mass number while 2 is the atomic number.

some sources quote the lethal dose, for an average 170lbs opiate-naive individual is between 75 and 375 mg