* Alpha particles are not neutral: They have a +2 charge, meaning they carry two positive charges. This is because an alpha particle is essentially a helium nucleus, containing two protons and two neutrons.

* Alpha particles have a relative mass of 4 amu: Protons and neutrons each have a relative mass of approximately 1 amu. Since an alpha particle contains two of each, its total relative mass is roughly 4 amu.

In summary:

* Charge: +2

* Relative Mass: 4 amu