two protons joined to two neutrons

An alpha particle is two protons joined to two neutrons.

helium nucleuses and neutrons

For instance, beta particles are electrons, alpha particles are helium nucleuses and neutrons are uncharged particles.

a helium nucleus without any electrons

An alpha particle is a helium nucleus without any electrons.

a type of ionizing radiation

Alpha particles are a type of ionizing radiation.

a helium nucleus - one of the products of a nuclear fission

The alpha particle is a helium nucleus - one of the products of a nuclear fission.

radiation

The type of radiation radium 223 uses is called alpha particles.

a helium nucleus, NOT a helium atom

An alpha particle is a helium nucleus, NOT a helium atom.

a particular type of ionizing radiation that can be shielded by material as thin as a piece of paper

Alpha particles are a particular type of ionizing radiation that can be shielded by material as thin as a piece of paper.

positively-charged helium nuclei

Alpha particles are positively-charged helium nuclei that, once produced by radon decay, tend to 'plate' out on airborne dust particles (and other substrates).

a type of ionizing radiation that is exerted from radioactive materials

An alpha particle is a type of ionizing radiation that is exerted from radioactive materials.

low-penetrating types of radiation

Alpha particles are low-penetrating types of radiation, and generally will not penetrate your skin and probably in all likelyhood, won’t penetrate your clothing.

a helium nucleus i.e. a helium atom that has lost i.e. a helium atom's two orbital electrons

The alpha particle is a helium nucleus i.e. a helium atom that has lost i.e. a helium atom's two orbital electrons.

a helium nucleus with a charge of +2 and a mass number of 4 (\(\ce{^{208}_{82}Pb}\)

For example, an alpha particle is a helium nucleus (\(\ce{^{208}_{82}Pb}\) with a charge of +2 and a mass number of 4, so a mass number is symbolized \(\ce{^4_2He}\).

the most damaging type of ionizing radiation encountered in medical radiology

Alpha particles are the most damaging type of ionizing radiation encountered in medical radiology; however, medical radiology can be stopped with an ordinary sheet of paper.

very low energy radiation

Alpha particles are very low energy radiation consisting of protons, nucleus's with no, or a few electrons.

just a helium nucleus and a Gamma ray

An Alpha particle is just a helium nucleus and a Gamma ray is a wave somewhat higher in frequency than the microwaves some hams play with.

just a He2+ ion

An alpha particle is a helium nucleus, which is the He2+ ion.

the most powerful radiation

Alpha particles are the most powerful radiation and consist of helium nuclei, which are bigger and strong than beta radiation – a stream of electrons.

a heat source in radioisotope thermoelectric generators, which are used to power some spacecraft

alpha particles is a heat source in radioisotope thermoelectric generators, which are used to power some spacecraft.

a proton an electron a neutron a positive electron electromagnetic radiation a helium nucleus

An alpha particle is: a proton an electron a neutron a positive electron electromagnetic radiation a helium nucleus