An alpha particle is identical to a helium nucleus with a mass number of _____ and electrostatic charge of _____.

An alpha particle is indeed identical to a helium nucleus, which consists of two protons and two neutrons. This structure gives it a mass number of 4 because the mass number is the total count of protons and neutrons in the nucleus. The electrostatic charge of the alpha particle comes from its two protons. Since protons carry a positive charge, the total charge of the alpha particle is +2.

This understanding directly supports the idea that an alpha particle, being a helium nucleus, has a mass number of 4 due to its two protons and two neutrons, and a charge of +2 due to its two protons.