Changes

An '''alpha particle''' is a positively charged [[particle]] (a [[Helium-4]] [[nucleus]]) made up of two [[neutron]]s and two [[proton]]s. It is the least penetrating of the three common forms of [[radiation]], being stopped by a sheet of paper. It is not dangerous to living things unless the alpha-emitting substance is inhaled or ingested or comes into contact with the [[lens]] of the [[eye]].

An '''alpha particle''' is a positively charged [[particle]] (a [[Helium-4]] [[nucleus]]) made up of two [[neutron]]s and two [[proton]]s. It is the least penetrating of the three common forms of [[radiation]], being stopped by a sheet of paper. It is not dangerous to living things unless the alpha-emitting substance is inhaled or ingested or comes into contact with the [[lens]] of the [[eye]].