The problem states that 24 11Na is radioactive. The question asks if it's a β- or β+ emitter. The 24 is the atomic mass number and the 11 is the atomic number.
I know that in β- decay, the atomic number increases by 1 and it emits an electron and antineutrino.
For β+ decay, the atomic number decreases by 1 and it emits a positron and neutrino.
The Attempt at a Solution
I know that 24-11 = 13 neutrons. So there are more neutrons than protons (11). How can I use this information to figure out if it will undergo β- or β+ decay?