Alpha particle

An alpha particle is essentially a <a href="Helium">helium</a> <a href="Nucleus">nucleus</a>; two <a href="Protons">protons</a> and two <a href="Neutrons">neutrons</a> held together by <a href="Strong nuclear force">strong nuclear forces</a>. Alpha particles are emitted when large unstable <a href="Nuclei">nuclei</a> undergo alpha decay to become smaller and more stable. <a href="Alpha radiation">Alpha radiation</a> is highly ionising, although the radiation can not pass through the barrier of skin, so inhalation or consumption of the <a href="Radioactive">radioactive</a> source are the main causes of harm from alpha particle emissionBreithaupt J. AQA physics A A2: student’s book. UK: Nelson Thornes. 2008..