In Beta decay, a neutron decays into a proton, and "throws out" an electron at high speed. However, this, to me, suggests that the law of conservation of mass is not being kept here.
Neutrons have a mass of "1",
Protons have a Mass of "1",
Electrons have a mass of "1/1840"
This means that, before the decay, the total mass is "1", but after the decay has occurred, the total mass in the system is "1841/1840", we have gained an electron's worth of mass from somewhere.
DISCLAIMER: I have been taught at a GCSE level, so much dumbing down has occurred in terms of what I have been taught. If I say something wrong, its because I've been taught that at school. Sorry!
This means that, either energy is being converted to mass here, or the "mass" values I have been taught are wrong, or the reason could be completely different. Which is it?
TL;DR: In beta decay, we seemingly gain one electron's worth of mass. Where has it come from?