A tiny mass of material composed of two protons and two neutrons. Alpha particles do not travel very far from their radioactive source. They cannot pass through a piece of paper, clothes or even the layer of dead cells which normally protects the skin. Because alpha particles cannot penetrate human skin they are not considered an "external exp [..]

Particle of matter that is positively charged. This particle consists of two neutrons and two protons and is emitted as a form of radioactivity from the nuclei of some radioisotopes. Also see beta par [..]

A particle that is commonly ejected from radioactive nuclei, consisting of two protons and two neutrons. Alpha particles are helium nuclei. Alpha particles have a mass of 6.644 655 98 × 10-27 kg or 4. [..]

Positively charged particle emitted by various radioactive materials during decay. It consists of two neutrons and two protons, and is thus identical to the nucleus of a helium atom. The rest mass of [..]

A particle consisting of two protons and two neutrons, produced during alpha decay. Identical to the nucleus of a 4He atom.

Click for a picture Alpha particle (Source: Medical Pages: http://www.irradiation.co.uk/types.php) A particle of 2 protons and 2 neutrons (essentially a helium nucleus) that is emitted by an unstable [..]

A positively charged particle ejected spontaneously from the nuclei of some radioactive elements. It is identical to a helium nucleus that has a mass number of 4 and an electrostatic charge of +2. It has low penetrating power and a short range (a few centimeters in air). The most energetic alpha particle will generally fail to penetrate the dead la [..]

A particle emitted spontaneously from the nuclei of some radioactive elements. It is identical with a helium nucleus, having a mass of four units and an electric charge of two positive units. The alph [..]

A radical Islamist terrorist organization established by Osama bin Laden (now deceased), responsible for a number of attacks in the United States and worldwide, including the September 11, 2001 attack [..]

An alpha particle is a He2+ion or the helium nucleus. This particle is commonly denoted by the Greek letter α.Return to the Chemistry Glossary Index

High-energy helium nucleus emitted during certain nuclear decay processes.

A positively-charged particle emitted from the nucleus of an atom during radioactive decay. Alpha particles are helium nuclei, with 2 protons and 2 neutrons.

The nucleus of a helium atom (two protons and two neutrons) emitted as radiation from a decaying heavy nucleus.

A positively charged particle emitted from the nucleus of an atom during radioactive decay and consists of two protons and two neutrons (a helium-4 nucleus). Although alpha particles are normally highly energetic, they travel only a few centimetres in air and are stopped by a sheet of paper or the outer layer of dead skin.

[noun] A type of particle that is ejected from radioactive nuclei. Alpha particles consist of two protons and two neutrons and thus are equivalent to helium nuclei. Appears in modules:

A positively charged particle ejected spontaneously from the nuclei of some radioactive elements. It is identical to a helium nucleus that has a mass number of 4 and an electric charge of +2. It has l [..]

A helium-4 nucleus, especially when emitted from the nucleus of a radioactive atom.

The nucleus of a helium atom (two protons and two neutrons) emitted as radiation from a decaying heavy nucleus; also known as an alpha ray

(Animation) the nucleus of a helium atom, made up of two neutrons and two protons with a charge of +2. Certain radioactive nuclei emit alpha particles. Alpha particles generally carry more energy than [..]

A helium nucleus (two protons and two neutrons) ejected from an unstable nucleus. α particles are stopped by a few centimetres of air, or a sheet of paper. They are strongly ionising radiation, due in [..]

A positively charged nucleus of a helium-4 atom (consisting of two protons and two neutrons), emitted as a consequence of radioactivity.

A positively charged particle ejected spontaneously from the nuclei of some radioactive elements. It is identical to a helium nucleus that has a mass number of 4 and an electric charge of +2. It has l [..]

A type of fast ion emitted by many types of heavy radioactive nuclei, such as uranium. Actually, the nucleus (atom stripped of all electrons) of the gas helium.

A positively charged particle emitted during the radioactive decay of some unstable atoms (Lesson 25)

(n.) A cluster of two protons and two neutrons; a helium nucleus.

                  An alpha particle  is:  A particle of nuclear radiation that is made up of two protons and two neutrons. It is therefore a helium nucleus with a nucleon number of 4 and a proton numb [..]

A positively charged particle emitted by certain radioactive material. It is made up of two neutrons and two protons; hence it is identical with the nucleus of a helium atom.

a helium nucleus; i.e., a helium atom that has lost two electrons.

A positively-charged particle emitted by radioactive atoms.  Alpha particles travel less than one inch in the air and a thin sheet of paper will stop them.   The main danger from alpha particles lies in ingesting the atoms which emit them.  Body cells next to the atom can then be irradiated over an extended period of time, which may be prolonged if [..]

Positively charged particles composed of two Protons and two Neutrons, i.e. equivalent to Helium nuclei, which are emitted during disintegration of heavy Isotopes. Alpha Rays have very strong ionizing [..]

Preferred term: bit rot

<physics> A radioactive particle made up of two protons and two neutrons, these particles are created by the decay of a radioactive material or by nuclear bombardment, and they are the same as the nucleus of a helium-4 atom. (09 Oct 1997)

An alpha particle is a particle with weight (it is made up of two protons and two neutrons) and charge (it is positively charged because protons have a positive charge). Alpha particles do not travel [..]

A positively charged particle consisting of two Neutrons and two protons which is emitted from Atoms undergoing Alpha Decay . The range of the alpha particle is short (a few cm&#39;s in air) and t [..]