Alpha particles are best described as:

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Alpha particles are helium-4 nuclei: a relatively heavy, positively charged particle produced in certain radioactive decays. They consist of two protons and two neutrons, giving them a large mass for a single radiation particle and a 2+ electric charge from the two protons. This combination explains both their strong interaction with matter and their limited range in air, as they are easily stopped by a sheet of paper. So the description that best fits is: a large-mass particle made of two protons and two neutrons carrying a 2+ charge. The other statements mischaracterize alpha particles: they do not travel far in air, they are not neutral, and they do carry charge.