# How is the atomic number of a beta particle zero?

In my textbook, $$\ce{β-}$$ particle is denoted as $$_{-1}e^0$$. This means that the atomic number of $$\ce{β-}$$ is $$\ce{-1}$$. But that doesn't make any sense. Also, how is the mass number of $$\ce{β-}$$ zero? I mean it must have some mass right? How can it be massless?

• I will start you off: mass number is not mass. Mass number is total protons plus neutrons, so it is zero for an electron.
– Ed V
Apr 24 at 11:09
• But what is the meaning of having atomic number equal to $-1$? Total number of protons equal to $-1$? That doesn't make any sense. Apr 24 at 12:09
• An electron has a negative charge, hasn't it ? Apr 24 at 12:15
• Get a better textbook, the authors of this one have no idea what they are writing about, or it's poor editorial job. Either way, beta particle is denoted with e, e⁻ or β⁻. All particle symbols are upright and the charge is denoted in a superscript. Apr 24 at 12:15
• Also, it is best not to dwell on such contrived stuff: people who write beginning level chemistry books often strive for an artificial consistency, leading to what you have encountered. I have seen it as well and been annoyed by it. So what @andselisk says is good advice: get a better book, if you have the opportunity.
– Ed V
Apr 24 at 12:24